Electroless copper plating method for PCBs (printed circuit boards) with high aspect ratios

Abstract

The invention discloses an electroless copper plating method for PCBs with high aspect ratios. According to the method, the intervals between adjacent PCBs with high aspect ratios are adjusted, and a plug board rack is enabled to swing in a an electroless copper plating potion in a direction perpendicular to the board surface, so that bubbles are discharged from holes in the PCBs with high aspect ratios; then electroless copper plating processes are performed twice on the PCBs with high aspect ratios, and total board electroplating flashing is performed on the PCBs after the primary electroless copper plating; accordingly, the thickness of copper on the hole wall is increased; and then the secondary total board plating is performed to thicken the copper. Compared with the prior art, the method effectively solves the problem that the circuit boards are scrapped due to copper absence in the holes caused by the fact that the bubbles in the holes cannot be cleared out or potion exchange in the holes is poor in the electroless copper plating process; and further, the total board electroplating flashing is adopted after the primary electroless copper plating process, therefore, the problem that original copper is corroded away in the secondary electroless copper plating pretreatment is solved, and accordingly, production scrapping is reduced effectively, and the manufacturing rework cost is reduced.

Description

Technical field: [0001] The invention belongs to the technical field of printed circuit board production, and in particular relates to an electroless copper deposition method for a PCB board with a high aspect ratio. Background technique: [0002] After the circuit board is pressed and drilled, in order to make the circuits of each layer conduct with each other, a thin layer of copper must be formed on the hole wall through the electroless copper deposition process, and then the hole wall copper is thickened by electroplating , to achieve good conduction of the lines of each layer. [0003] As the number of PCB layers becomes higher and the thickness of the board becomes thicker, the aperture design on the circuit board becomes smaller and smaller. For PCBs with a high aspect ratio greater than or equal to 8:1, due to the smaller Small, in the process of copper sinking, the air bubbles in the hole cannot be driven out or the liquid exchange in the hole is not good, which ca...

AI Technical Summary

Problems solved by technology

[0004] For this reason, the object of the present invention is to provide a kind of electroless copper deposition method of high aspect ratio PCB board, to solve the current high aspect ratio PCB board in the process of copper sinking because the air bubbles in the hole cannot be driven out or the liquid medicine exchange in the hole is not good. Leading to no copper in the hole, causing the circuit board to be scrapped