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CN-121240352-B - PCB blind hole silver filling device and silver filling method

CN121240352BCN 121240352 BCN121240352 BCN 121240352BCN-121240352-B

Abstract

The invention discloses a blind hole silver filling device and a silver filling method for a PCB, which relate to the technical field of PCB electroplating and comprise a positioning base arranged at the center line position of the bottom of an electroplating bath, a positioning hanging seat detachably arranged at the top of the electroplating bath and used for clamping a circuit board to be plated with silver, a side spray pipe vertically arranged along the depth direction of the electroplating bath and spraying silver plating liquid towards the circuit board, a bottom spray pipe transversely arranged parallel to the electroplating bath and obliquely upwards spraying silver plating liquid to strengthen liquid disturbance, a movable spray pipe capable of moving along the length direction of the electroplating bath and rotating around the axis of the electroplating bath and throwing silver plating liquid towards the side surface of the circuit board and deep into a blind hole, a plurality of groups of spray pipes connected with a liquid supply pipe of the electroplating bath and used for cooperatively supplying silver spraying liquid, and a multi-directional spray and dynamic rotary silver spraying mechanism is used for forming a compound circulation in the blind hole, so that the deposition uniformity and compactness of the silver layer in the circuit board and the blind hole are improved, and the problems of limited liquid flow and uneven silver layer in the electroplating of the blind hole of the existing circuit board are solved.

Inventors

  • ZHU JIANWEN
  • LI CHUNMIAO
  • WANG JIANFENG

Assignees

  • 江门诺华精密电子有限公司

Dates

Publication Date
20260512
Application Date
20251113

Claims (6)

  1. 1. A blind hole silver filling device for a PCB board is characterized by comprising a plating bath, a positioning base, a positioning hanging seat, a side spray pipe, a bottom spray pipe and a movable spray pipe, wherein the positioning base is arranged at the bottom central line position of the plating bath, the positioning hanging seat is detachably arranged at the top central line position of the plating bath, the positioning base is used for positioning and clamping the bottom of a circuit board to be plated with silver, the positioning hanging seat is used for positioning and clamping the top of the circuit board, the length direction of the side spray pipe is vertically arranged along the depth direction of the plating bath and is provided with a plurality of spray pipes along the length direction of the plating bath, the side spray pipe sprays silver plating liquid towards the side surface of the circuit board, the length direction of the bottom spray pipe is parallel to the transverse direction of the plating bath, is arranged at the bottom of the plating bath, and sprays silver plating liquid towards the side surface of the circuit board in a controllable rhythm manner, and is used for improving the disturbance degree of liquid in the bath; the bottom of the circuit board is inserted into the positioning base along with the positioning hanging seat arranged on the electroplating bath, and the circuit board is fixed in the electroplating bath; The electroplating device comprises an electroplating bath, a movable spray pipe, a linear moving module, a linear moving sliding block, a movable spray pipe and a movable spray pipe, wherein the linear moving module is arranged above the electroplating bath and along the length direction of the electroplating bath; A rotating unit is arranged on the movable sliding block and comprises a rotating base, a rotating motor and a rotating ring; the rotary base extends out of the movable sliding block to form a hollow cantilever, the top and the bottom in the hollow cantilever are respectively provided with a plane bearing, and the rotary ring is sleeved between the two plane bearings; the inner ring of the rotating ring is provided with a key slot, the movable spray pipe penetrates through the inner ring of the rotating ring to extend into the electroplating bath, the fixed end of the movable spray pipe is provided with convex key teeth and is fixedly bonded with the key slot, the outer ring of the rotating ring is provided with transmission teeth, the rotating motor is arranged on the rotating base, the output shaft of the rotating motor is provided with a transmission gear, the transmission gear is meshed with the rotating ring for transmission, and the rotating motor drives the rotating ring to drive the movable spray pipe to swing back and forth towards the left side, the front side and the right side of the circuit board, so that silver plating liquid is thrown out in a fan shape; The liquid supply pipe is connected with the top of the fixed end of the movable spray pipe, so that silver plating liquid flows into the movable spray pipe from top to bottom, a plurality of third taper nozzles of 15 degrees are arranged on the movable spray pipe from top to bottom along the length direction of the movable spray pipe, and the third taper nozzles are arranged towards the circuit board.
  2. 2. The device for filling silver into the blind hole of the PCB of claim 1, wherein the side spray pipe is provided with a plurality of first taper nozzles of 60 degrees in the electroplating bath from top to bottom along the length direction, and the first taper nozzles are arranged towards the circuit board.
  3. 3. The blind hole silver-filling device for the PCB according to claim 2, wherein a control valve for controlling the injection rhythm is arranged between the first taper nozzle and the side spray pipe.
  4. 4. The blind hole silver-filling device for the PCB according to claim 1, wherein the bottom spray pipe is sequentially provided with a plurality of second taper nozzles of 30 degrees along the length direction, and the second taper nozzles are arranged towards the circuit board.
  5. 5. The device for filling silver into the blind hole of the PCB according to claim 4, wherein four second taper nozzles are arranged on the bottom spray pipe, the four second taper nozzles are sequentially arranged at 65 degrees, 55 degrees, 45 degrees and 35 degrees obliquely upwards along the direction from the side wall of the electroplating bath to the side surface of the circuit board, and the tail ends of the four second taper nozzles are arranged on the same inclined plane.
  6. 6. S1, preparing a workpiece, namely, after pre-cleaning and surface activating the circuit board, arranging the circuit board between a positioning base and a positioning hanging seat of an electroplating bath; the method comprises the steps of S2, initializing liquid circulation and injection, starting liquid supply of an electroplating bath, enabling silver plating liquid to be synchronously supplied from a side spray pipe, a bottom spray pipe and a movable spray pipe, starting injection, S3, controlling a first taper spray nozzle in the side spray pipe to sequentially spray according to a layered rhythm from top to bottom, enabling the silver plating liquid to cover the side wall and an orifice area of a blind hole of a circuit board at different incidence angles, forming stable circulation distribution, S4, dynamically moving and rotating the silver spray pipe, starting a linear moving module and a rotating unit, driving the movable spray pipe to move along the length direction of the electroplating bath and rotate around the axis of the movable spray pipe at a controllable rotating speed, and carrying out periodic intensified silver spraying on the blind hole at different areas by adjusting the round trip frequency and the rotating angle speed of the movable spray pipe, S5, synchronously electroplating, and synchronously controlling the electroplating, dynamically adjusting the spray flow and the moving rhythm of the movable spray pipe according to a multi-point current feedback signal in the electroplating bath, and automatically optimizing the pressure of the movable spray pipe when the current density deviation exceeds a set threshold value, and the spray pipe thickness of the blind hole is detected, and the quality of the silver plating board is sequentially detected, and the quality of the dry circuit board is dried after the dry is dried, and the dry circuit board is dried.

Description

PCB blind hole silver filling device and silver filling method Technical Field The invention relates to the technical field of PCB electroplating, in particular to a PCB blind hole silver filling device and a silver filling method. Background The PCB (Printed Circuit Board ) is used as an important basic carrier for electronic element connection and signal transmission, and the conductivity and reliability of the PCB directly influence the performance stability of the whole product. In order to realize multilayer wiring and high-density interconnection in a limited space, modern high-density interconnection (HDI) technology widely adopts a Micro Blind Via (Micro Blind Via) structure to realize interlayer electrical connection. Blind holes are usually formed by laser drilling or mechanical drilling and are filled with metal in an electroplating process to form a conductive via, wherein silver is widely used in a via metallization process of a high-end PCB board due to its excellent electrical conductivity and oxidation resistance. The existing blind hole silver filling technology is mainly completed through an electroplating or chemical replacement process, and the process is mostly of a groove type electroplating structure, and is matched with a vibration, swing or ultrasonic auxiliary mode to promote electrolyte to circularly flow in the blind hole, so that the silver ion deposition rate is improved. However, because the blind hole has smaller aperture and larger depth diameter, and Kong Naliu body exchange is limited, the vibration or swinging mode can only improve the surface electric field distribution, so that the full silver coating on the inner wall of the blind hole is difficult to realize, the problems of local dead angle, uneven thickness of a silver layer, insufficient deposition of a hole bottom and the like easily occur, and the conductive consistency and the welding reliability of the through hole are affected. In addition, the conventional partial improvement scheme tries to optimize the current distribution by changing the electrode layout or adding an auxiliary anode, but the flow field and the electric field inside the tiny blind holes still are difficult to accurately control, and particularly in the complex structure of the multi-layer PCB, the traditional vertical electroplating liquid flow mode cannot fully enter the hole bottom area, so that the deposition efficiency of the silver layer at the bottom and the side wall of the blind holes is low, the coverage rate is insufficient, and the subsequent electric performance fluctuation and the reliability are reduced. According to the defects, the side spraying type silver spraying equipment is introduced in the production process by enterprises, and the silver solution is sprayed to the side wall and the hole bottom area of the blind hole of the PCB by high kinetic energy through arranging the multi-angle side spraying nozzle in the electroplating bath, so that the updating speed of liquid in the blind hole and the distribution uniformity of silver ions are obviously improved. The mode shows higher compactness of the silver layer and coverage rate in the hole in experiments, and becomes an important development direction of a blind hole precise silver filling process. However, the side spraying structure at the present stage still has the problems of difficult precise control of spraying angle, uneven spraying pressure distribution, high risk of nozzle blockage and the like, and a systematic and adjustable silver filling device and a matching method are not formed yet. In summary, it is found that the prior art has at least the following technical problems: The existing blind hole silver filling equipment for the circuit board has the technical problems that electrolyte flow in holes is limited, and silver layer deposition is uneven. Disclosure of Invention The invention aims to provide a blind hole silver filling device and a silver filling method for a PCB (printed circuit board) to solve the technical problems that the flow of electrolyte in holes is limited and silver layer deposition is uneven in the existing blind hole silver filling equipment for the PCB. The preferred technical solutions of the technical solutions provided by the present invention can produce a plurality of technical effects described below. In order to solve the technical problems, the invention provides the following technical scheme: The invention provides a PCB blind hole silver filling device which comprises a plating bath, a positioning base, a positioning hanging seat, a side spray pipe, a bottom spray pipe and a movable spray pipe, wherein the positioning base is arranged at the bottom central line position of the plating bath, the positioning hanging seat is detachably arranged at the top central line position of the plating bath, the positioning base is used for positioning and clamping the bottom of a circuit board to be plated with silver, the positioni