A manufacturing method of PCB back drill hole

Abstract

The invention discloses a manufacturing method of PCB back drill hole, which comprises the following steps: laminating, drilling through holes, chemical copper precipitation, electroplating copper, whole plate tin plating, drilling back drilling, tin removing, pre-drying plate, resin plug hole, drying plate and grinding plate; Wherein the back drill hole is a back drill hole having a special structure, wherein the depth ratio of the back drill hole depth to the through hole depth is greater than or equal to 1, and the depth of the back drill hole is greater than or equal to 0.5 mm; The pre-drying plate retains the residual temperature of the plate surface, and the residual temperature is higher than the ambient temperature for resin plug holes; The resin plug hole is plugged in such a waythat resin ink flows into the back hole from the through hole of the plate, and the whole back hole and the through hole are filled. The invention increases the plumpness of the plug hole of the backhole with the special structure, and improves the uniformity and reliability of the plug hole of the back hole with the special structure.

Description

technical field [0001] The invention relates to the technical field of multilayer microstrip board production, in particular to a method for manufacturing PCB back-drilled holes and resin plugging holes. Background technique [0002] In the PCB manufacturing process, through holes are needed to realize the connection between the inner layers. The through holes are usually formed by drilling machines, which require high processing accuracy. After drilling through holes, they need to undergo copper sinking, electroplating, etc. , forming a conductive layer in the through hole, so as to realize the connection between the inner layer lines, but the plated through holes of some PCB boards only need partial conduction, and the through holes after sinking copper and electroplating are all conduction Yes, this will cause the problem of connection at the end of the through hole, which will lead to the return of the signal, resulting in reflection, scattering, delay and other phenomen...

AI Technical Summary

Problems solved by technology

[0005] The traditional plug hole method can meet the plug hole requirements of ordinary back-drilled holes, but when the back-drilled hole is a back-drilled hole with a special structure, that is, the depth ratio of the back-drilled hole depth to the via hole depth is greater than or equal to 1, And when the back-drilling depth is greater than or equal to 0.5mm, the traditional plugging method is used to flow the resin ink from the back-drilling hole of the board into the via hole. Since the depth of the back-drilling hole is greater than or equal to the depth of the via hole, that is The volume of the back-drilled hole is large. When the via hole is filled, the back-drilled hole is not yet filled, which will make the air in the back-drilled hole unable to be completely removed. When the subsequent baking board is processed, the air will be heated and expanded, resulting in The resin in the back-drilled hole overflows, causing voids or depressions in the back-drilled hole. In the subsequent cap plating, the hole metallization solution enters the back-drilled hole, resulting in a short circuit in the back-drilled hole

Therefore, the traditional plug hole method cannot meet the uniformity and fullness requirements of the back-drilled plug hole with a special structure

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