Multi-layer circuit board via hole non-stub preparation device

Abstract

The invention discloses a multi-layer circuit board via hole non-stub preparation device, and relates to the field of multi-layer circuit board preparation, the multi-layer circuit board via hole non-stub preparation device comprises a multi-layer circuit board and a processing groove used for processing the surface of the multi-layer circuit board, the multi-layer circuit board is provided with a plurality of through holes, and the processing groove is fixedly connected with a moving track. A vertical moving assembly is fixedly connected to the moving end of the moving rail and used for driving the vertical moving assembly to move in the length direction of the processing groove. Local plugging of the through hole is achieved through the plugging assembly, the through hole is divided into a copper-plating-free area and a target copper-plating area through the two silicon rubber cases on the plug, only electroplating liquid is allowed to enter the target copper-plating area through the open hole in the connecting pipe, and generation of redundant copper columns is eradicated fundamentally; meanwhile, the check ring precisely limits the insertion depth of the plug, it is ensured that the copper plating area is precisely positioned, interference of the stub on high-speed signal transmission is effectively avoided, the signal integrity and reliability of the multi-layer circuit board are improved, and the use requirements of high-end electronic equipment are met.

Description

A device for preparing vias without residual stubs on multilayer circuit boards Technical Field

[0001] This invention relates to the field of multilayer circuit board fabrication technology, and specifically to a device for fabricating multilayer circuit board vias without residual stubs. Background Technology

[0002] As electronic devices develop towards miniaturization, high speed, and high density, the application of multilayer circuit boards is becoming more and more widespread. As the core structure for interconnecting the circuits of each layer of a multilayer circuit board, the processing quality of vias directly affects the signal transmission performance and reliability of the circuit board.

[0003] Currently, copper plating of vias in multilayer circuit boards mostly employs the traditional back-drilling process. This process first performs full-wall copper plating on the through-holes penetrating the multilayer circuit board, and then removes excess copper pillars (residual stubs) within the through-holes that do not participate in signal transmission through back drilling, in order to reduce signal reflection and attenuation. However, this process has several drawbacks: First, the drill bit is prone to deviation during back drilling, making it impossible to completely remove residual stubs. The remaining residual stubs can still interfere with high-speed signal transmission, leading to a decrease in signal integrity and failing to meet the requirements of high-end electronic devices. Second, drilling to remove residual stubs after full-wall copper plating is a cumbersome process with low processing efficiency, and it also increases the consumption of copper plating solution, raising production costs. Third, back drilling can easily damage the copper layer on the inner wall of the through-hole, affecting the conductivity and lifespan of the via. Summary of the Invention

[0004] The purpose of this invention is to provide a device for preparing vias without residual stubs on multilayer circuit boards in order to solve the above-mentioned problems, as detailed below.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A multilayer circuit board via-hole preparation device provides a multilayer circuit board, comprising a multilayer circuit board and a processing groove for processing the surface of the multilayer circuit board. The multilayer circuit board has several through holes. A moving track is fixedly connected to the processing groove. A vertical moving component is fixedly connected to the moving end of the moving track, for driving the vertical moving component to move along the length of the processing groove. A swinging component is rotatably connected to the vertical moving component, and a sealing component is fixedly connected to the swinging component for partially sealing the inner wall of the through holes. The vertical moving component drives the swinging component to move upwards, enabling the swinging component to move the multilayer circuit board from horizontal to inclined.

[0006] Preferably, a first support platform and a second support platform are fixedly connected to both sides of the processing tank along its length.

[0007] Preferably, the treatment tank is provided with separate pre-immersion tank, activation tank, electroplating tank and cleaning tank in sequence.

[0008] Preferably, the vertical moving component includes a mounting frame fixedly connected to the moving end of the moving track, an electric push rod fixedly connected vertically to the mounting frame, a guide sleeve fixedly connected to the mounting frame, a movable rod slidably connected inside the guide sleeve, and the movable end of the electric push rod fixedly connected to the movable rod.

[0009] Preferably, the swing component includes a swing rod rotatably connected to the movable rod, the swing rod being fixedly connected to an arc-shaped rod via a connecting rod, the movable rod having a channel and being slidably connected to the arc-shaped rod via the channel, a spring being sleeved on the arc-shaped rod, the two ends of the spring being fixedly connected to the connecting rod and the movable rod respectively, an elbow being fixedly connected to the end of the arc-shaped rod away from the connecting rod, and a push rod being fixedly connected to the mounting bracket to block the elbow.

[0010] Preferably, the sealing assembly includes a connecting frame fixedly connected to the swing rod, and a plurality of plugs are fixedly connected to the connecting frame, the plugs being inserted into the through hole.

[0011] Preferably, the plug includes a connecting tube with two silicone sleeves on its surface. The connecting tube has an opening between the two silicone sleeves, and the silicone sleeves are in clearance fit with the inner wall of the through hole.

[0012] Preferably, the connecting tube is fixedly connected to the connecting frame, two silicone sleeves are vertically distributed on the connecting tube, and a retaining ring is fixedly connected to the upper silicone sleeve to limit the depth of the plug insertion through hole.

[0013] Preferably, a detachment component is fixedly connected to the first support platform, which is used to cooperate with the upward movement of the vertical moving component to detach the multilayer circuit board from the sealing component.

[0014] Preferably, the detachment assembly includes at least two stops fixedly connected to the first support platform, and the stops are capable of corresponding to the top of the multilayer circuit board.

[0015] The beneficial effects are as follows: 1. The sealing component achieves partial sealing of through holes. The two silicone sleeves on the plug divide the through hole into an area that does not require copper plating and an area that is intended for copper plating. The opening on the connecting tube only allows the electroplating solution to enter the area intended for copper plating, thus eliminating the generation of excess copper pillars from the source. At the same time, the retaining ring precisely limits the insertion depth of the plug, ensuring accurate positioning of the copper plating area, effectively avoiding interference from residual pillars to high-speed signal transmission, improving the signal integrity and reliability of multilayer circuit boards, and meeting the usage requirements of high-end electronic equipment.

[0016] 2. By precisely defining the copper plating area through the sealing component, local copper plating can be directly achieved, reducing the back drilling process, shortening the processing cycle, and improving processing efficiency.

[0017] 3. Through the coordinated operation of the moving track and the vertical moving component, the multi-layer circuit board is automatically transferred and lifted between the pre-immersion tank, activation tank, electroplating tank and cleaning tank, eliminating the need for manual transfer. At the same time, the swinging component enables the automatic tilting of the multi-layer circuit board to ensure rapid liquid backflow. The detachment component enables the automatic and non-destructive detachment of the sealing component from the multi-layer circuit board. The entire process is automated, reducing manual intervention and human error, and further improving processing accuracy and stability.

[0018] 4. By directly connecting the sealing component to the through hole of the circuit board, compared with the existing technology of using hooks to hang the circuit board, the connection is tighter and the positioning is more secure. It can effectively fix the circuit board and prevent the circuit board from shaking during electroplating and transportation. The stability of the circuit board can ensure that it has uniform contact with the treatment liquid in each tank, preventing problems such as uneven copper plating thickness and local missing plating caused by shaking, further ensuring copper plating quality and improving product consistency. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 is a perspective view of the present invention; Figure 2 is a front view of the present invention; Figure 3 is a perspective view of the vertical moving component of the present invention; Figure 4 is a perspective cross-sectional view of the multilayer circuit board of the present invention; Figure 5 is a perspective view of the sealing component of the present invention; Figure 6 is a perspective view of the second support platform of the present invention.

[0021] The reference numerals in the attached drawings are explained as follows: 1. Processing tank; 101. Pre-impregnation tank; 102. Activation tank; 103. Electroplating tank; 104. Cleaning tank; 2. Moving track; 3. First support platform; 4. Detachment component; 401. Stop bar; 5. Second support platform; 6. Sealing component; 601. Connecting frame; 602. Block; 6021. Connecting pipe; 6022. Silicone sleeve; 6023. Retaining ring; 6024. Opening; 7. Vertical moving component; 701. Mounting frame; 702. Electric push rod; 703. Guide sleeve; 704. Movable rod; 8. Swinging component; 801. Swing rod; 802. Connecting rod; 803. Arc rod; 804. Spring; 805. Elbow; 806. Push rod; 9. Multilayer circuit board; 901. Through hole. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] Referring to Figures 1-6, the present invention provides a device for preparing vias without residual stubs on multilayer circuit boards, including a multilayer circuit board 9 and a processing groove 1 for processing the surface of the multilayer circuit board 9. The multilayer circuit board 9 has a plurality of through holes 901. A moving track 2 is fixedly connected to the processing groove 1. A vertical moving component 7 is fixedly connected to the moving end of the moving track 2 for driving the vertical moving component 7 to move along the length direction of the processing groove 1. A swinging component 8 is rotatably connected to the vertical moving component 7. A sealing component 6 is fixedly connected to the swinging component 8 for partially sealing the inner wall of the through holes 901. The vertical moving component 7 drives the swinging component 8 to move upward, so that the swinging component 8 can drive the multilayer circuit board 9 from horizontal to inclined.

[0024] A first support platform 3 and a second support platform 5 are fixedly connected to both sides of the processing tank 1 along its length. A disengagement component 4 is fixedly connected to the first support platform 3, which is used to disengage the multilayer circuit board 9 from the sealing component 6 in conjunction with the upward movement of the vertical moving component 7. The disengagement component 4 includes at least two stops 401 fixedly connected to the first support platform 3, and the stops 401 can correspond to the top of the multilayer circuit board 9.

[0025] The processing tank 1 contains, in sequence, independent pre-impregnation tank 101, activation tank 102, electroplating tank 103, and cleaning tank 104. The pre-impregnation tank 101 contains a pre-impregnation solution, primarily a weakly acidic solution, such as a 5%-10% sulfuric acid solution or a specialized PCB pre-impregnating agent. Its function is to remove the slight oxide layer, residual resin debris, and mold release agent from the exposed substrate surface of the through-hole 901, while simultaneously adjusting the surface potential of the hole wall to lay the foundation for subsequent activation treatment and prevent impurities from affecting copper layer adhesion. The activation tank 102 is filled with an activation solution, primarily a palladium salt solution, such as palladium chloride solution, with a small amount of hydrochloric acid to adjust the acidity. Its function is to deposit a uniform layer of palladium particles on the inner wall of the blind hole, forming catalytic centers that trigger the autocatalytic reaction of subsequent electroless copper plating, ensuring that copper ions are uniformly and firmly deposited on the hole wall, preventing problems such as copper plating peeling and uneven plating. The cleaning tank 104 is filled with a cleaning solution used to clean the electroplating solution inside the through-hole 901.

[0026] Referring to Figures 1, 2, and 3, the vertical moving component 7 includes a mounting frame 701 fixedly connected to the moving end of the moving track 2. An electric push rod 702 is vertically fixedly connected to the mounting frame 701. A guide sleeve 703 is fixedly connected to the mounting frame 701. A movable rod 704 is slidably connected inside the guide sleeve 703. The movable end of the electric push rod 702 is fixedly connected to the movable rod 704. The swinging component 8 includes a swinging rod 801 rotatably connected to the movable rod 704. An arc-shaped rod 803 is fixedly connected to the swinging rod 801 through a connecting rod 802. A channel is opened in the movable rod 704, and it is slidably connected to the arc-shaped rod 803 through the channel. A spring 804 is sleeved on the arc-shaped rod 803. The two ends of the spring 804 are fixedly connected to the connecting rod 802 and the movable rod 704, respectively. An elbow 805 is fixedly connected to the end of the arc-shaped rod 803 away from the connecting rod 802. A push rod 806 is fixedly connected to the mounting frame 701 to block the elbow 805.

[0027] In this embodiment, the electric push rod 702 drives the movable rod 704 to move vertically, and the movable rod 704 drives the multilayer circuit board 9 to move downward, so that the multilayer circuit board 9 is immersed in the treatment tank 1. The vertical moving component 7 cooperates with the moving track 2 to make the multilayer circuit board 9 enter and exit the pre-immersion tank 101, the activation tank 102, the electroplating tank 103 and the cleaning tank 104 in sequence. It should be noted that after the multilayer circuit board 9 is moved onto the treatment tank 1, it can tilt in cooperation with the swing component 8, so that the liquid on the multilayer circuit board 9 can quickly flow back to the treatment tank 1. Specifically, the movable rod 704 drives the arc rod 803 to move upward. When the arc rod 803 contacts the push rod 806, the arc rod 803 moves upward with the movable rod 704. The arc rod 803 is pushed by the push rod 806, so that the arc rod 803 rotates. The arc rod 803 drives the connecting rod 802, so that the swing rod 801 drives the sealing component 6 and the multilayer circuit board 9 to rotate. The spring 804 is used to reset the swing rod 801, so that the multilayer circuit board 9 is horizontal.

[0028] Referring to Figures 4 and 5, the sealing assembly 6 includes a connecting frame 601 fixedly connected to the swing rod 801. Several plugs 602 are fixedly connected to the connecting frame 601, and the plugs 602 are inserted into the through hole 901. Each plug 602 includes a connecting tube 6021 with two silicone sleeves 6022 on its surface. An opening 6024 is formed on the connecting tube 6021, located between the two silicone sleeves 6022. The silicone sleeves 6022 are clearance-fitted with the inner wall of the through hole 901. The connecting tube 6021 is fixedly connected to the connecting frame 601. The two silicone sleeves 6022 are vertically distributed on the connecting tube 6021, and a retaining ring 6023 is fixedly connected to the upper silicone sleeve 6022 to limit the insertion depth of the plug 602 into the through hole 901.

[0029] In this embodiment, the plug 602 is used to insert into the through hole 901 to seal the part of the electroplating tube that is not needed. The silicone sleeve 6022 of the plug 602 is in clearance fit with the inner wall of the through hole 901. When the through hole 901 is immersed in the electroplating tank 103, the electroplating solution flows into the connecting pipe 6021 and enters the through hole 901 through the opening 6024, so as to achieve partial electroplating of the inner wall of the through hole 901. After electroplating, the multilayer circuit board 9 enters the cleaning tank 104 to clean the excess electroplating solution. Finally, it moves to the first support platform 3 through the moving track 2. At that time, the stop bar 401 is located on the multilayer circuit board 9. Then, the vertical moving component 7 drives the sealing component 6 to move upward, so that the sealing component 6 is separated from the through hole 901. It should be noted that the thickness of the electroplating layer is very thin, so the plug 602 will not interfere with it when it is pulled out.

[0030] After the plug 602 is inserted into the through hole 901, the silicone sleeve 6022 on its surface forms a tight clearance fit with the inner wall of the through hole 901. At the same time, the retaining ring 6023 limits the insertion depth of the plug 602 and limits the multilayer circuit board 9, which can realize the stable connection between the plugging component 6 and the multilayer circuit board 9, and ensure that the multilayer circuit board 9 will not fall off during transportation, electroplating and tilting backflow.

[0031] The working principle of this invention is as follows: The sealing component 6 is fixed to the swing rod 801 by the connecting frame 601. The plug 602 on the connecting frame 601 corresponds one-to-one with the through hole 901 of the multilayer circuit board 9. When the plug 602 is inserted into the through hole 901, the insertion depth is limited by the retaining ring 6023 of the upper silicone sleeve 6022 to ensure accurate positioning. The two silicone sleeves 6022 are fitted with the inner wall of the through hole 901 with a gap, dividing the through hole 901 into areas that do not require copper plating. The opening 6024 on the connecting tube 6021 is located in the target copper plating area, providing a channel for the electroplating solution to enter, thereby achieving precise definition of the copper plating area.

[0032] The moving track 2 drives the vertical moving component 7 to move horizontally along the length of the processing tank 1, realizing the transfer of the multilayer circuit board 9 between the tanks. The electric push rod 702 of the vertical moving component 7 drives the movable rod 704 to slide vertically along the guide sleeve 703, thereby driving the swing component 8, the sealing component 6, and the multilayer circuit board 9 to rise and fall, realizing the action of the circuit board immersing or detaching from each tank. When the electric push rod 702 drives the movable rod 704 to rise, the arc rod 803 rises synchronously with the movable rod 704. After the elbow 805 contacts the push rod 806, it is blocked, forcing the arc rod 803 to drive the swing rod 801 to rotate, thereby causing the multilayer circuit board 9 to move from the tank. The horizontal axis is tilted to allow the liquid to flow back to the corresponding tank quickly. When the movable rod 704 descends, the spring 804 resets and drives all components back to their original positions, restoring the circuit board to a horizontal position. After the post-plating cleaning is completed, the moving track 2 transports the multi-layer circuit board 9 to the top of the first support platform 3, with the stop rod 401 located on top of the circuit board. The electric push rod 702 drives the movable rod 704 and the sealing assembly 6 to rise, while the stop rod 401 blocks the circuit board from rising, causing the block 602 and the through hole 901 to move relative to each other, achieving non-destructive separation. After separation, the circuit board is placed on the first support platform 3, and the second support platform 5 is used to place the circuit board waiting to be processed, completing a single processing cycle.

[0033] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A device for preparing vias without residual stubs on multilayer circuit boards, characterized in that: The device includes a multilayer circuit board (9) and a processing groove (1) for processing the surface of the multilayer circuit board (9). The multilayer circuit board (9) has several through holes (901). A moving track (2) is fixedly connected to the processing groove (1). A vertical moving component (7) is fixedly connected to the moving end of the moving track (2) for driving the vertical moving component (7) to move along the length of the processing groove (1). A swinging component (8) is rotatably connected to the vertical moving component (7). A sealing component (6) is fixedly connected to the swinging component (8) for partially sealing the inner wall of the through holes (901). The vertical moving component (7) drives the swinging component (8) to move upward, so that the swinging component (8) can drive the multilayer circuit board (9) from horizontal to inclined.

2. The apparatus for preparing vias without residual stubs on multilayer circuit boards according to claim 1, characterized in that: The processing tank (1) has a first support platform (3) and a second support platform (5) fixedly connected to both sides along its length.

3. The multilayer circuit board via-hole preparation device without residual stubs according to claim 2, characterized in that: The processing tank (1) is provided with a pre-immersion tank (101), an activation tank (102), an electroplating tank (103), and a cleaning tank (104) in sequence.

4. The device for preparing vias without residual stubs on multilayer circuit boards according to claim 1, characterized in that: The vertical moving component (7) includes a mounting frame (701) fixedly connected to the moving end of the moving track (2). An electric push rod (702) is vertically fixedly connected to the mounting frame (701). A guide sleeve (703) is fixedly connected to the mounting frame (701). A movable rod (704) is slidably connected inside the guide sleeve (703). The movable end of the electric push rod (702) is fixedly connected to the movable rod (704).

5. The multilayer circuit board via-hole preparation device without residual stubs according to claim 4, characterized in that: The swing component (8) includes a swing rod (801) rotatably connected to the movable rod (704). The swing rod (801) is fixedly connected to an arc rod (803) via a connecting rod (802). The movable rod (704) has a channel and is slidably connected to the arc rod (803) through the channel. A spring (804) is sleeved on the arc rod (803). The two ends of the spring (804) are fixedly connected to the connecting rod (802) and the movable rod (704) respectively. An elbow (805) is fixedly connected to one end of the arc rod (803) away from the connecting rod (802). A push rod (806) is fixedly connected to the mounting bracket (701) to block the elbow (805).

6. The apparatus for preparing vias without residual stubs on multilayer circuit boards according to claim 5, characterized in that: The sealing assembly (6) includes a connecting frame (601) fixedly connected to the swing rod (801), and a plurality of plugs (602) are fixedly connected to the connecting frame (601), and the plugs (602) are inserted into the through hole (901).

7. The apparatus for preparing vias without residual stubs on multilayer circuit boards according to claim 6, characterized in that: The plug (602) includes a connecting pipe (6021), the surface of which is provided with two silicone sleeves (6022), and an opening (6024) is provided on the connecting pipe (6021), and the opening (6024) is located between the two silicone sleeves (6022), and the silicone sleeves (6022) are clearance-fitted with the inner wall of the through hole (901).

8. The apparatus for preparing vias without residual stubs on multilayer circuit boards according to claim 7, characterized in that: The connecting tube (6021) is fixedly connected to the connecting frame (601), and two silicone sleeves (6022) are vertically distributed on the connecting tube (6021). A retaining ring (6023) is fixedly connected to the upper silicone sleeve (6022) to limit the depth of the plug (602) inserted into the through hole (901).

9. The apparatus for preparing vias without residual stubs on multilayer circuit boards according to claim 1, characterized in that: The first support platform (3) is fixedly connected to a detachment component (4), which is used to cooperate with the upward movement of the vertical moving component (7) to detach the multilayer circuit board (9) from the sealing component (6).

10. The apparatus for preparing vias without residual stubs on a multilayer circuit board according to claim 9, characterized in that: The detachment component (4) includes at least two stops (401) fixedly connected to the first support platform (3), and the stops (401) can correspond to the top of the multilayer circuit board (9).

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