Manufacturing method of circuit board

Abstract

The invention discloses a manufacturing method of a circuit board, and belongs to the technical field of circuit board manufacturing, and the method comprises the steps: transferring an electrogilding circuit and a pattern to a PCB, and after the PCB with the circuit and the pattern transferred is obtained, protecting a conductive wire between LGA areas by using photosensitive wet ink, and protecting other patterns by using a dry film to obtain the PCB with an exposed copper surface; performing electrogilding treatment on the PCB with the exposed copper surface to obtain an electrogilded PCB; covering the PCB subjected to gold electroplating with a protective material, and exposing the to-be-etched conductive wire and the corresponding etching liquid medicine outflow channel through exposure of a negative film; feeding the exposed PCB into etching line equipment to etch a conductive wire, and completing the manufacturing of the circuit board; according to the invention, the problem of poor corrosion of a gold surface caused by the fact that the gold surface is attacked by residual etching liquid medicine when the LGA gold-plated pattern is used for etching a conductive wire is solved.

Description

Technical Field

[0001] The invention relates to a method for manufacturing a circuit board, and belongs to the technical field of circuit board manufacturing. Background Art

[0002] The LGA of traditional circuit boards is mainly used for welding, so chemical nickel-gold or OSP surface treatment has basically met the needs of circuit boards in practical applications. However, with the continuous upgrading of products, the LGA area of ​​​​the circuit board sometimes needs to be repeatedly contacted and mounted, and traditional chemical nickel-gold or OSP cannot solve the problem that the LGA area cannot resist wear during repeated use. Therefore, in order to improve the wear resistance of LGA, the process demand for LGA electroplating gold has gradually emerged. The existing LGA electroplating gold process is to first draw a conductive wire in the electroplating gold area, and then conduct the electroplating gold equipment and the gold-plated PAD in the LGA area by drawing the conductive wire, so as to achieve electroplating gold in the LGA area. After the circuit board is electroplated with gold, the drawn conductive wire needs to be etched away with etching solution (other areas are protected with dry film) to avoid short circuit of the circuit board network due to the conductive wire remaining on the circuit board. Although the process of this process is now relatively mature, it has many requirements for the design of the circuit board; for example: when etching the conductive wire in the LGA area, a dry film negative is made according to the distribution of the conductive wire (exposing the conductive wire), and the residual etching solution in the dry film will attack the gold surface, resulting in poor appearance and affecting customer assembly.

[0003] At present, with the change of the demand for printed circuit boards, the use scenarios of traditional electroplating gold have also changed greatly. The traditional BGA welding method can no longer meet the technical requirements of large chips and high speeds. At the same time, the BGA assembly method of LGA can overcome the above shortcomings to meet the needs of high-speed products. However, due to the signal requirements in the LGA area, people are often unwilling to accept the presence of copper and nickel on the gold surface. Therefore, this process of first electroplating gold on the conductive wire and then etching the conductive wire can solve the problem of gold plating for some special products, but the problem of residual etching solution attacking the gold surface can no longer meet the needs of current products. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for manufacturing a circuit board, which overcomes the problem of corrosion of the gold surface caused by residual etching solution attacking the gold surface when etching conductive lines of LGA gold-plated patterns.

[0005] To achieve the above object, the present invention is implemented by adopting the following technical solutions: In a first aspect, the present invention provides a method for manufacturing a circuit board, comprising: Transferring the electroplated gold circuits and patterns to the PCB board to obtain a PCB board with the transferred circuits and patterns; In the PCB board after the circuit and pattern are transferred, the conductive lines between the LGA areas are protected with photosensitive wet ink, and the remaining patterns are protected with dry film to obtain a PCB board with exposed copper surface; Performing gold electroplating on the exposed copper surface of the PCB to obtain a gold-plated PCB; Cover the PCB board after gold electroplating with protective material, and expose the conductive wires to be etched and the corresponding etching solution outflow channel through film exposure; The exposed PCB board is sent to the etching line equipment to etch the conductive lines to complete the circuit board production.

[0006] Furthermore, the method also includes: after obtaining the gold-plated PCB board, using a degumming solution to remove the residual photosensitive wet ink and dry film on the surface of the gold-plated PCB board.

[0007] Furthermore, the method further comprises: removing residual protective material after etching the conductive line.

[0008] Furthermore, the photosensitive wet ink is a light-curing material, which is used to protect the conductive wires between the LGA areas from being gold-plated during the gold electroplating process.

[0009] Furthermore, the film exposure process includes: performing exposure operation using a pre-designed film, and exposing the conductive wires to be etched and the corresponding etching solution outflow channels by controlling the exposure time and light intensity.

[0010] Furthermore, the film design method includes: automatically designing the film for the conductive line area of ​​the LGA area through a preset program, and avoiding the gold electroplating area of ​​the LGA area.

[0011] Furthermore, the method also includes: automatically identifying the spacing between the etching solution outflow channels through a preset program, and performing a repair operation to ensure that the etching solution outflow channels can discharge the etching solution in a timely manner.

[0012] Furthermore, the process of etching the conductive line includes: sending the exposed PCB board into the etching line equipment, and the etching liquid flows along the etching solution outflow channel and contacts the copper surface to be etched, and the etching liquid chemically reacts with the exposed copper surface to etch away the unnecessary copper layer.

[0013] Furthermore, the method also includes: after the transfer circuit and the pattern are completed, confirming that the size, spacing, copper thickness and appearance inspection meet the set specifications.

[0014] Furthermore, the method also includes: after the circuit board is manufactured, performing an appearance inspection on the circuit board to check whether the LGA area has a poor gold surface appearance.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for manufacturing a circuit board, which overcomes the problem of corrosion of the gold surface caused by residual etching solution attacking the gold surface when etching the conductive line of an LGA gold-plated pattern, by covering a protective material on the PCB board after gold electroplating, and exposing the conductive line to be etched and the corresponding etching solution outflow channel through a negative film. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flowchart of a method for manufacturing a circuit board provided by an embodiment of the present invention.

[0017] Figure 2 is a top view of the LGA area of ​​a PCB board provided by an embodiment of the present invention; Figure 3 is a schematic diagram of a PCB board covered with protective material provided by an embodiment of the present invention; Figure 4 is a schematic diagram of film exposure provided by an embodiment of the present invention; Figure 5 is a schematic diagram of a PCB board after development provided by an embodiment of the present invention; Figure 6 is a schematic diagram of a PCB board after etching provided by an embodiment of the present invention; Figure 7 It is a schematic diagram of a PCB board after removing the protective material provided by an embodiment of the present invention.

[0018] In the figure: 1. Copper that needs to be electroplated with gold; 2. The spacing between copper and conductive lines; 3. Electroplated gold LGA area protection material; 4. Film exposure area. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0020] Embodiment 1: This embodiment introduces a method for manufacturing a circuit board, comprising: Transferring the electroplated gold circuits and patterns to the PCB board to obtain a PCB board with the transferred circuits and patterns; In the PCB board after the circuit and pattern are transferred, the conductive lines between the LGA areas are protected with photosensitive wet ink, and the remaining patterns are protected with dry film to obtain a PCB board with exposed copper surface; Performing gold electroplating on the exposed copper surface of the PCB to obtain a gold-plated PCB; Cover the PCB board after gold electroplating with protective material, and expose the conductive wires to be etched and the corresponding etching solution outflow channel through film exposure; The exposed PCB board is sent to the etching line equipment to etch the conductive lines to complete the circuit board production.

[0021] like Figure 1-Figure 7 As shown in the figure, 1 is copper that needs to be electroplated with gold; 2 is the spacing between copper and copper and the conductive wire; 3 is the electroplated gold LGA area protection material; 4 is the film exposure area; the method for manufacturing a circuit board provided in this embodiment can be used in a printed circuit board, and the method requires that the LGA area has no poor gold surface appearance, which mainly includes the following steps: (1) Transfer the electroplated gold circuits and patterns to the PCB board to obtain the PCB board after the transferred circuits and patterns are completed; after the transfer circuits and patterns are completed, confirm that the size, spacing, copper thickness and appearance inspection meet the specifications; (2) Use photosensitive wet ink (cured by light) to protect the conductive wires between the LGAs from gold plating, and use dry film to protect the remaining patterns to obtain a PCB board with exposed copper surface; (3) electroplating the PCB board with the exposed copper surface with gold to obtain a PCB board after electroplating with gold; using a degumming solution (alkaline) to remove the residual protective layer on the surface of the PCB board after electroplating with gold to complete the electroplating with gold; (4) Send the gold-plated product into the laminator and cover the PCB with a layer of protective material, which can protect the entire PCB; obtain the PCB covered with the protective material; use the film to expose the conductive wires to be etched and the corresponding etching solution outflow channel (hereinafter referred to as the "channel"). The specific film operation steps are as follows: a. The film channel framework of the LGA area is established, and the channel avoidance area is obtained at the same time. The program automatically produces the film data of the conductive wire in the LGA area, and then avoids the electroplating gold area of ​​the LGA area; b. Use the program to automatically identify the distance between water channels. If the distance is beyond the analytical capability of the protective material, the program will automatically identify and repair it. Once the water channels that can drain the etching solution in time are opened, the etching exposure film work is completed; (5) Expose the film data using the etching exposure method of the water channel, exposing the conductive wires and water channel parts that need to be etched; (6) Sending the product to the etching line equipment to etch the conductive wire; (7) Removing the remaining protective material layer after etching the conductive lines; (8) Appearance inspection, quality confirmation, and shipment.

[0022] The above invention is compared with the traditional film design as shown in Table 1 below: Table 1

[0023] The steps of the programmed production method for etching the "opening channel" film are shown in Table 2 below: Table 2

[0024] Note: According to the above method, there may still be isolated cover films or small width of local cover films, which can be regarded as normal design.

[0025] The present embodiment provides a method for manufacturing a circuit board, which overcomes the problem of corrosion of the gold surface caused by residual etching solution attacking the gold surface when etching the conductive lines of the LGA gold-plated pattern, by covering the PCB board with a protective material after gold plating, and exposing the conductive lines to be etched and the corresponding etching solution outflow channels through a negative film.

[0026] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for manufacturing a circuit board, characterized in that: include: Transferring the electroplated gold circuits and patterns to the PCB board to obtain a PCB board with the transferred circuits and patterns; In the PCB board after the circuit and pattern are transferred, the conductive lines between the LGA areas are protected with photosensitive wet ink, and the remaining patterns are protected with dry film to obtain a PCB board with exposed copper surface; Performing gold electroplating on the exposed copper surface of the PCB to obtain a gold-plated PCB; Cover the PCB board after gold electroplating with protective material, and expose the conductive wires to be etched and the corresponding etching solution outflow channel through film exposure; The exposed PCB board is sent to the etching line equipment to etch the conductive lines to complete the circuit board production.

2. The method for manufacturing a circuit board according to claim 1, characterized in that: The method further comprises: after obtaining the gold-plated PCB board, using a degumming solution to remove the residual photosensitive wet ink and dry film on the surface of the gold-plated PCB board.

3. The method for manufacturing a circuit board according to claim 1, characterized in that: The method further includes removing residual protection material after etching the conductive line.

4. The method for manufacturing a circuit board according to claim 1, characterized in that: The photosensitive wet ink is a light-curing material used to protect the conductive wires between the LGA areas from being gold-plated during the gold electroplating process.

5. The method for manufacturing a circuit board according to claim 1, characterized in that: The film exposure process includes: performing exposure operation using a pre-designed film, and exposing the conductive lines to be etched and the corresponding etching solution outflow channels by controlling the exposure time and light intensity.

6. The method for manufacturing a circuit board according to claim 5, characterized in that: The film design method comprises: automatically designing the film for the conductive line area of ​​the LGA area through a preset program, and avoiding the electroplated gold area of ​​the LGA area.

7. The method for manufacturing a circuit board according to claim 1, characterized in that: The method further includes: automatically identifying the spacing between the etching solution outflow channels through a preset program, and performing a repair operation to ensure that the etching solution outflow channels can discharge the etching solution in time.

8. The method for manufacturing a circuit board according to claim 1, characterized in that: The process of etching the conductive line includes: sending the exposed PCB board into the etching line equipment, and the etching liquid flows along the etching solution outflow channel and contacts the copper surface to be etched, and the etching liquid chemically reacts with the exposed copper surface to etch away the unnecessary copper layer.

9. The method for manufacturing a circuit board according to claim 1, characterized in that: The method also includes: After the transfer circuit and the pattern are completed, confirming that the size, spacing, copper thickness and appearance inspection meet the set specifications.

10. The method for manufacturing a circuit board according to claim 1, characterized in that: The method further comprises: after the circuit board is manufactured, performing an appearance inspection on the circuit board to check if there is any poor appearance of the gold surface in the LGA area.

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