Cleaning method and device for improving gold dipping and palladium removal of NPTH hole and printed circuit board

Abstract

The invention relates to a cleaning method and device for improving gold dipping and palladium removal of an NPTH hole and a printed circuit board. The method comprises the following steps: performing palladium removal treatment on the NPTH hole of the PCB through palladium removal liquid medicine; micro-etching: cleaning the palladium removal liquid medicine on the PCB through micro-etching liquid medicine; performing first overflow cleaning, namely cleaning sulfuric acid components of the PCB by spraying water; carrying out first HFS water washing, and cleaning the sulfuric acid component of the PCB through high-frequency water washing; according to the method, the steps of cleaning palladium ions left in the NPTH hole of the PCB, drying, drying the surface of the PCB and the interior of the hole and the like are carried out, the palladium ions left in the NPTH hole of the PCB are cleaned up, and the problem of palladium removal of the NPTH hole is effectively solved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of PCB manufacturing, and specifically to a method and device for improving the cleaning of NPTH holes for gold removal and palladium removal, and a printed circuit board. Background Art

[0002] Immersion gold PCB refers to the process of plating a metal layer on the circuit surface by chemical deposition during the circuit production process. Since the copper solder joints on the circuit board are easily oxidized, the circuit board after immersion gold can prevent surface oxidation, improve the color, facilitate subsequent welding, and ensure performance and quality. For immersion gold boards that have not undergone the palladium removal process, palladium ions are adsorbed on the NPTH hole wall of the board surface during copper deposition. When immersion gold is applied, the palladium ions on the NPTH hole wall react with the nickel cylinder solution, causing nickel gold to be deposited on the NPTH hole wall. Therefore, it is necessary to remove palladium by washing, and then go through processes such as grinding and micro-etching to solve the problem of nickel gold on the NPTH hole.

[0003] The current palladium removal method is mainly carried out through water washing, which uses high-pressure water flow to impact the plate surface. Due to the different distribution of impact points, it is often impossible to directly impact the NPTH hole wall, resulting in a long cleaning time and incomplete palladium removal effect. Summary of the invention

[0004] In view of the above problems, the embodiments of the present invention provide a method, device and printed circuit board for improving the cleaning of NPTH hole gold-stained palladium removal, which is used to solve the problem that the palladium removal method in the prior art is mainly carried out by water washing, and the high-pressure water flow impacts the board surface. Due to the different distribution of the impact points, it is often unable to directly impact the NPTH hole wall, resulting in a long cleaning time and incomplete palladium removal effect.

[0005] According to one aspect of an embodiment of the present invention, a method for improving the cleaning of NPTH holes by removing gold and palladium is provided, the method comprising: Put the PCB board with NPTH holes into the cleaning equipment; Removing palladium, performing palladium removal treatment on the NPTH hole of the PCB board by using a palladium removal solution; Micro-etching, using micro-etching solution to clean the palladium removal solution on the PCB board; The first overflow cleaning uses spray water to clean the sulfuric acid components on the PCB board; The first HFS washing is to clean the sulfuric acid components of the PCB board through high-frequency washing; Drying: Dry the surface and holes of the PCB board.

[0006] In some optional embodiments, after the HFS washing and before the drying, the method further comprises: Precision grinding, using mechanical pressure to remove foreign matter from the board surface and roughen the copper surface; The first pressurized water washing is to wash away foreign matter remaining on the PCB board through high-pressure water washing.

[0007] In some optional embodiments, after the first pressurized water washing and before the drying, the method further includes: Super roughening: use super roughening solution to perform super roughening treatment on the surface of the PCB board; The second overflow cleaning uses spray water to clean the super-roughening solution on the PCB board; The second HFS washing is to clean the super-roughening solution of the PCB board through high-frequency washing.

[0008] In some optional embodiments, after the second HFS washing and before the drying, the method further comprises: Hydrochloric acid washing: washing the PCB board with hydrochloric acid solution; The third overflow cleaning is to clean the hydrochloric acid solution on the PCB board by spraying water; The second pressurized water washing is to rinse the hydrochloric acid solution remaining on the PCB board through high-pressure water washing.

[0009] In some optional embodiments, after the second pressurized water washing and before the drying, the method further includes: Ultrasonic immersion cleaning: clean the PCB board surface and foreign matter in the hole through ultrasonic immersion cleaning; The third HFS washing process uses high-frequency washing to clean the PCB board surface and foreign matter in the holes. The third pressurized water washing is to clean the foreign matter on the surface of the PCB board and in the holes through high-pressure water washing.

[0010] In some optional embodiments, after the third pressurized water washing and before the drying, the method further comprises: Dry the board surface and use the PVA absorbent sponge roller to absorb the residual moisture on the board surface and in the holes of the PCB board.

[0011] In some optional embodiments, the palladium removal solution consists of 0.4-0.8 mol / L hydrochloric acid, 50-80 g / L thiourea and the balance water.

[0012] In some optional embodiments, in the drying step, the PCB board is placed in a baking machine for drying, wherein the temperature of the baking machine is 100°C-150°C, and the baking time is: 2H-4H.

[0013] According to another aspect of an embodiment of the present invention, a device for improving the cleaning of NPTH holes for gold removal and palladium removal is provided, and the device is used to perform the above-mentioned method for improving the cleaning of NPTH holes for gold removal and palladium removal to manufacture a printed circuit board.

[0014] According to another aspect of an embodiment of the present invention, a printed circuit board is provided, and the printed circuit board is manufactured by executing the above-mentioned improved NPTH hole gold-deposited palladium-removing cleaning method by the above-mentioned improved NPTH hole gold-deposited palladium-removing cleaning device.

[0015] The method, device and printed circuit board for improving the cleaning of NPTH holes by removing gold and palladium of the present invention have the following beneficial effects: 1. The present invention performs palladium removal treatment on the NPTH hole of the PCB board by palladium removal solution; micro-etching, cleaning the palladium removal solution on the PCB board by micro-etching solution; the first overflow cleaning, cleaning the sulfuric acid component of the PCB board by spraying water; the first HFS water washing, cleaning the sulfuric acid component of the PCB board by high-frequency water washing; drying, drying the board surface and the inside of the hole of the PCB board, etc., to clean the residual palladium ions in the NPTH hole of the PCB board, and effectively solve the problem of palladium removal of the NPTH hole.

[0016] 2. The present invention also cleans the PCB board after palladium removal by precision grinding, super-roughening, hydrochloric acid washing, ultrasonic immersion and corresponding water washing operations in sequence, and performs deep and comprehensive cleaning on the NPTH holes of the PCB board, so as to completely remove the palladium ions in the NPTH holes, prevent the NPTH holes from being stuck with gold, and effectively improve the yield rate of PCB board production.

[0017] The above description is only an overview of the technical solution of the embodiment of the present invention. In order to more clearly understand the technical means of the embodiment of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are only used to illustrate the embodiments and are not to be considered as limiting the present invention. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings. In the accompanying drawings: Figure 1 A schematic flow chart of a method for improving the cleaning of NPTH holes for removing gold and palladium according to Example 1 of the present invention is shown; Figure 2 A schematic flow chart of the precision grinding plate and related steps of Example 1 provided by the present invention is shown; Figure 3 A schematic flow chart of the ultra-roughening and related steps of Example 1 provided by the present invention is shown; Figure 4 A schematic flow chart of hydrochloric acid washing and related steps of Example 1 provided by the present invention is shown; Figure 5A schematic flow chart of ultrasonic immersion cleaning and related steps of Example 1 provided by the present invention is shown. DETAILED DESCRIPTION

[0019] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0020] Embodiment 1: See also Figure 1 The embodiment of the present invention provides a method for improving the palladium removal of gold in NPTH holes. The method is used to clean the palladium ions in the NPTH holes of the PCB board. The method is cleaned by a multi-station cleaning line, wherein the multi-station cleaning line includes multiple cleaning stations, such as a palladium removal station, a micro-etching station, an overflow cleaning station, etc. The cleaning stations can be connected in sequence through a conveyor belt. The method includes: 110, put the board into the cleaning equipment after making the NPTH hole; in step 110, the cleaning equipment can be a palladium removal cleaning machine or a multi-station cleaning line. In this example, the cleaning equipment is a multi-station cleaning line. Specifically, after the NPTH hole of the PCB board is made, the board can be automatically placed using a robotic arm, and the delay time can be adjusted according to the board thickness and line speed to ensure that the spacing between the boards is ≥5cm to avoid board jamming.

[0021] 120, palladium removal, palladium removal treatment is performed on the NPTH holes of the PCB board by palladium removal solution; in step 120, the PCB board is transferred to the palladium removal machine through a conveyor belt, and the palladium removal machine is provided with palladium removal agent tanks for spraying palladium removal agent on the upper and lower sides of the PCB. The conveyor belt drives the PCB to move, and the palladium removal agent is sprayed on the PCB from the upper and lower sides of the PCB respectively. The palladium removal solution is composed of 0.4-0.8mol / L hydrochloric acid, 50-80g / L thiourea and the remainder of water. The spraying pressure of the palladium removal solution is 2.0kg / cm 2 The transmission speed of the conveyor belt is 4m / min, and the effective spray length of the palladium removal tank is 40cm.

[0022] 130, micro-etching, cleaning the palladium removal solution on the PCB board with micro-etching solution; in step 130, the PCB board is transferred to the micro-etching station through a conveyor belt, and the palladium removal solution on the PCB board can be cleaned with a micro-etching solution composed of sulfuric acid, hydrogen peroxide, water-soluble metal salts, micro-etching stabilizers, etc. In this step, not only the palladium removal solution can be removed, but also foreign matter such as metal on the PCB board can be cleaned, thereby increasing the palladium removal effect.

[0023] 140, the first overflow cleaning, the sulfuric acid components of the PCB board are cleaned by spraying water; in step 140, the overflow cleaning is a process of circulating the cleaning liquid and cleaning the PCB board with clean water. Specifically, the PCB board is transferred to the overflow cleaning station by a conveyor belt, and the sulfuric acid components on the board surface are cleaned by spraying water.

[0024] 150, the first HFS water washing, the sulfuric acid component of the PCB board is cleaned by high-frequency water washing; in step 150, the PCB board is transferred to the HFS water washing station through a conveyor belt, and the HFS water washing is carried out by a mixture of water and fluorinated acid; HFS water washing can effectively remove tiny dirt and oxides on the surface of the PCB board, ensuring the reliability and stability of the PCB board.

[0025] 160, drying, drying the board surface and the holes of the PCB board. In step 150, the PCB board is transferred to the baking station via a conveyor belt. In the drying step, the PCB board is placed in a baking machine for drying, wherein the temperature of the baking machine is 100°C-150°C, and the baking time is: 2H-4H. Specifically, the baking temperature can be 120°C, and the baking time is 2H, which can effectively remove moisture from the surface of the PCB board.

[0026] The present invention performs palladium removal treatment on the NPTH hole of the PCB board by using palladium removal solution; micro-etching, cleaning the palladium removal solution on the PCB board by using micro-etching solution; first overflow cleaning, cleaning the sulfuric acid component of the PCB board by spraying water; first HFS water washing, cleaning the sulfuric acid component of the PCB board by high-frequency water washing; drying, drying the board surface and the inside of the hole of the PCB board, etc., to clean the residual palladium ions in the NPTH hole of the PCB board, and effectively solve the problem of palladium removal of the NPTH hole.

[0027] In some optional embodiments, see Figure 2 , after one HFS washing and before drying, also includes: 210, precision grinding, removing foreign matter from the board surface and roughening the copper surface by mechanical pressure; In step 210, mechanical pressure is used to remove oil stains, foreign matter, oxide layer and roughen the copper surface. The surface of the PCB can be effectively treated, and palladium can be further removed by physical means to improve the palladium removal effect.

[0028] 220, the first pressurized water washing, using high pressure water washing to wash away foreign matter remaining on the PCB board. In step 220, the pressure of the pressurized water washing is set between 0.3MPa and 0.5MPa, and the copper powder and foreign matter remaining on the board surface are washed away by high pressure water washing.

[0029] In this embodiment, palladium is further removed from the NPTH hole of the PCB board through steps 210-220, thereby further improving the palladium removal effect. Meanwhile, abnormalities generated in the precision grinding step can be cleaned through step 220, thereby further reflecting the cleaning effect of the PCB board.

[0030] In some optional embodiments, see Figure 3 , after the first pressure water wash and before drying, also including: 310, super-roughening, the board surface of the PCB board is super-roughened by super-roughening solution; in step 310, super-roughening can form a rough structure on the surface of the copper foil through chemical reaction. This method usually uses a chemical solution containing ingredients such as an oxidant, a complexing agent and a surfactant, immerses the copper foil in the solution and stirs or heats it appropriately, so that the surface of the copper foil undergoes oxidation, reduction and other reactions, thereby forming a rough copper surface. Super-roughening can also form a rough structure on the surface of the copper foil through physical methods such as mechanical grinding, laser treatment, etc. The board surface is super-roughened to increase the bonding force of the ink to the copper surface. In step 310, not only can the surface of the PCB board be cleaned to avoid the presence of palladium ions. At the same time, it can also prepare for the solder mask step, reduce the preparation work of the solder mask step, save the PCB board production process, and improve the production efficiency of the PCB board.

[0031] 320, the second overflow cleaning, the super roughening solution of the PCB board is cleaned by spraying water; in step 320, the overflow cleaning is a process of circulating the cleaning liquid and cleaning the PCB board with clean water. Specifically, the PCB board is transferred to the overflow cleaning station by a conveyor belt to rinse the super roughening solution on the board surface.

[0032] 330, the second HFS washing, the ultra-roughening solution of the PCB board is cleaned by high-frequency washing. In step 330, the PCB board is transferred to the HFS washing station through a conveyor belt, and the HFS washing is a mixture of water and fluorinated acid for washing; HFS washing can effectively remove the tiny dirt and oxides on the surface of the PCB board, ensuring the reliability and stability of the PCB board.

[0033] In this embodiment, steps 310-330 can not only clean the surface of the PCB board to avoid the presence of palladium ions by treating the surface of the PCB board, but also prepare for the solder mask step, reduce the preparation work of the solder mask step, save the PCB board production process, and improve the production efficiency of the PCB board.

[0034] In some optional embodiments, see Figure 4 , after the second HFS washing and before drying, further comprising: 410, hydrochloric acid washing, hydrochloric acid washing the PCB board with hydrochloric acid solution; in step 410, hydrochloric acid washing can remove oxides, dirt and residues on the surface of the PCB board, make the surface of the PCB board smooth, and improve the reliability and performance of the PCB board. The hydrochloric acid solution is mainly composed of hydrochloric acid and water. In this step, the NPTH hole of the PCB board is further cleaned to avoid the residue of palladium ions and their compounds, and further improve the palladium removal effect.

[0035] 420, the third overflow cleaning, the hydrochloric acid solution on the PCB board is cleaned by spraying water; in step 420, the overflow cleaning is a process of circulating the cleaning liquid and cleaning the PCB board with clean water. Specifically, the PCB board is transferred to the overflow cleaning station through a conveyor belt, and the hydrochloric acid solution on the PCB board is cleaned by spraying water.

[0036] 430, a second pressurized water wash, wherein the hydrochloric acid solution remaining on the PCB board is washed away by high-pressure water washing. In step 430, the pressure of the pressurized water wash is set between 0.3MPa and 0.5MPa, and the hydrochloric acid solution remaining on the PCB board is washed away by high-pressure water washing.

[0037] In this embodiment, the NPTH holes of the PCB board are cleaned through steps 410-430 to avoid the residue of palladium ions and their compounds, thereby further improving the palladium removal effect.

[0038] In some optional embodiments, see Figure 5 , after the second pressure water washing and before drying, further comprising: 510, ultrasonic immersion cleaning, the foreign matter on the board surface and in the hole of the PCB board is cleaned by ultrasonic immersion cleaning; in step 510, the PCB board is transferred to the ultrasonic cleaning equipment by transmission, and the high-frequency vibration generated by ultrasonic waves in the cleaning liquid is used to remove the stains and residues on the surface of the PCB board. Among them, ultrasonic cleaning can clean the PCB board by combining low-frequency band and high-frequency band, such as the low-frequency band is set to 15~30kHz; the high-frequency band is set to above 40kHz.

[0039] 520, the third HFS water washing, the foreign matter on the board surface and in the hole of the PCB board is cleaned by high-frequency water washing; in step 520, the PCB board is transferred to the HFS water washing station through the conveyor belt, and the HFS water washing is carried out by a mixture of water and fluorinated acid; HFS water washing can effectively remove the tiny dirt and oxide on the surface of the PCB board, ensuring the reliability and stability of the PCB board.

[0040] 530, the third pressurized water washing, the foreign matter on the board surface and the hole of the PCB board is cleaned by high pressure water washing. In step 530, the pressure of the pressurized water washing is set between 0.3MPa and 0.5MPa, and the foreign matter on the board surface and the hole of the PCB board is cleaned by high pressure water washing.

[0041] In this embodiment, the precision grinding, super-roughening, and hydrochloric acid washing in steps 510-530 can not only further remove palladium ions, but also effectively remove the residual chemicals in each washing process.

[0042] In some optional embodiments, after the third pressurized water washing and before drying, the process further includes: drying the board surface, using a PVA water-absorbing sponge roller to absorb the residual water on the board surface and in the holes of the PCB board. In this embodiment, by using a PVA water-absorbing sponge roller to clean the board surface and in the holes of the PCB board, most of the water on the PCB board can be removed from a large area, saving drying time.

[0043] Embodiment 2: According to another aspect of an embodiment of the present invention, a device for improving the gold-deposited palladium removal cleaning of NPTH holes is provided, and the device is used to perform the above-mentioned method for improving the gold-deposited palladium removal cleaning of NPTH holes to manufacture printed circuit boards. The device for improving the gold-deposited palladium removal cleaning of NPTH holes of the present invention may include a multi-station cleaning line for cleaning, wherein the multi-station cleaning line includes multiple cleaning stations, such as a palladium removal station, a micro-etching station, an overflow cleaning station, etc., and the cleaning stations can be connected in sequence through a conveyor belt. The present invention removes palladium from the NPTH holes of the PCB board by palladium removal using a palladium removal solution; micro-etching, cleaning the palladium removal solution on the PCB board with a micro-etching solution; the first overflow cleaning, cleaning the sulfuric acid component of the PCB board by spraying water; the first HFS water washing, cleaning the sulfuric acid component of the PCB board by high-frequency water washing; drying, drying the board surface and the hole of the PCB board, etc., to clean the residual palladium ions in the NPTH holes of the PCB board, effectively solving the problem of palladium removal of the NPTH holes. The present invention also cleans the PCB board after palladium removal by precision grinding, super-roughening, hydrochloric acid washing, ultrasonic immersion and corresponding water washing operations in sequence, and performs deep and comprehensive cleaning on the NPTH holes of the PCB board, so as to completely remove the palladium ions in the NPTH holes, prevent the NPTH holes from being stuck with gold, and effectively improve the yield rate of PCB board production.

[0044] Embodiment 3: According to another aspect of an embodiment of the present invention, a printed circuit board is provided, and the printed circuit board is manufactured by performing an improved NPTH hole gold removal and palladium cleaning method as described above by the improved NPTH hole gold removal and palladium cleaning device. In this embodiment, after the printed circuit board is cleaned by the improved NPTH hole gold removal and palladium cleaning method, the ratio of gold adhesion in the NPTH hole is 0, and this method can completely solve the problem of NPTH gold adhesion. The present invention removes palladium from the NPTH hole of the PCB board by palladium removal solution; micro-etching, cleaning the palladium removal solution on the PCB board by micro-etching solution; the first overflow cleaning, cleaning the sulfuric acid component of the PCB board by spraying water; the first HFS water washing, cleaning the sulfuric acid component of the PCB board by high-frequency water washing; drying, drying the board surface and the hole of the PCB board, etc., to clean the residual palladium ions in the NPTH hole of the PCB board, effectively solving the problem of palladium removal of the NPTH hole. The present invention also cleans the PCB board after palladium removal by precision grinding, super-roughening, hydrochloric acid washing, ultrasonic immersion and corresponding water washing operations in sequence, and performs deep and comprehensive cleaning on the NPTH holes of the PCB board, so as to completely remove the palladium ions in the NPTH holes, prevent the NPTH holes from being stuck with gold, and effectively improve the yield rate of PCB board production.

[0045] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. Similarly, in order to simplify the present invention and help understand one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, the various features of the embodiments of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. Wherein, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, wherein each claim itself is a separate embodiment of the present invention.

[0046] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and further may be divided into a plurality of submodules or subunits or subcomponents. Except that at least some of such features and / or processes or units are mutually exclusive.

[0047] It should be noted that the above embodiments illustrate the present invention rather than limit it, and that those skilled in the art may design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of multiple such elements. The present invention may be implemented with the aid of hardware comprising several different elements and with the aid of appropriately programmed computers. In a unit claim that lists several systems, several of these systems may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be understood as limitations on the order of execution.

Claims

1. A method for improving the cleaning of NPTH holes by removing gold and palladium, characterized in that: The method comprises: Put the PCB board with NPTH holes into the cleaning equipment; Removing palladium, performing palladium removal treatment on the NPTH hole of the PCB board by using a palladium removal solution; Micro-etching, using micro-etching solution to clean the palladium removal solution on the PCB board; The first overflow cleaning uses spray water to clean the sulfuric acid components on the PCB board; The first HFS washing is to clean the sulfuric acid components of the PCB board through high-frequency washing; Drying: Dry the surface and holes of the PCB board.

2. The method for improving the gold removal and palladium removal of NPTH holes according to claim 1, characterized in that: After the HFS washing and before the drying, the method further comprises: Precision grinding, using mechanical pressure to remove foreign matter from the board surface and roughen the copper surface; The first pressurized water washing is to wash away foreign matter remaining on the PCB board through high-pressure water washing.

3. The method for improving the gold removal and palladium removal of NPTH holes according to claim 2, characterized in that: After the first pressurized water washing and before the drying, the method further comprises: Super roughening: use super roughening solution to perform super roughening treatment on the surface of the PCB board; The second overflow cleaning uses spray water to clean the super-roughening solution on the PCB board; The second HFS washing is to clean the super-roughening solution of the PCB board through high-frequency washing.

4. The method for improving the gold-removal and palladium-removal cleaning of NPTH holes according to claim 3, characterized in that: After the second HFS washing and before the drying, the method further comprises: Hydrochloric acid washing: washing the PCB board with hydrochloric acid solution; The third overflow cleaning is to clean the hydrochloric acid solution on the PCB board by spraying water; The second pressurized water washing is to rinse the hydrochloric acid solution remaining on the PCB board through high-pressure water washing.

5. The method for improving the gold-removal and palladium-removal cleaning of NPTH holes according to claim 4, characterized in that: After the second pressurized water washing and before the drying, the method further comprises: Ultrasonic immersion cleaning: clean the PCB board surface and foreign matter in the hole through ultrasonic immersion cleaning; The third HFS washing process uses high-frequency washing to clean the PCB board surface and foreign matter in the holes. The third pressurized water washing is to clean the foreign matter on the surface of the PCB board and in the holes through high-pressure water washing.

6. The method for improving the gold-removal and palladium-removal cleaning of NPTH holes according to claim 5, characterized in that: After the third pressurized water washing and before the drying, the method further comprises: Dry the board surface and use the PVA absorbent sponge roller to absorb the residual moisture on the board surface and in the holes of the PCB board.

7. The method for improving the gold-removal and palladium-removal cleaning of NPTH holes according to claim 1, characterized in that: The palladium removal solution is composed of 0.4-0.8 mol / L hydrochloric acid, 50-80 g / L thiourea and the balance water.

8. The method for improving the gold-removal and palladium-removal cleaning of NPTH holes according to claim 1, characterized in that: In the drying step, the PCB board is placed in a baking machine for drying, wherein the temperature of the baking machine is 100°C-150°C, and the baking time is: 2H-4H.

9. A cleaning device for improving the gold removal of NPTH holes, characterized in that: The device is used to implement the improved NPTH hole gold-staining and palladium-removing cleaning method as described in any one of claims 1 to 8 to manufacture printed circuit boards.

10. A printed circuit board, characterized in that: The printed circuit board is manufactured by using the improved NPTH hole gold removal and palladium cleaning device according to claim 9 to perform the improved NPTH hole gold removal and palladium cleaning method according to any one of claims 1 to 8.

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