Method for backdrilling via stubs of multilayer printed circuit boards with reduced backdrill diameters

摘要

Methods of backdrilling printed circuit boards (PCBs) to remove via stubs and related apparatuses. The method may include removing a via stub through a combination of backdrilling and chemical etching. The backdrilling may remove a masking layer from the via stub. Portions of an underlying layer may remain in the region of the via stub after the backdrilling is completed. The remaining portions of the underlying layer may be removed in a subsequent etching process thereby removing the via stub from the PCB. As the backdrilling step may be used for the limited purpose of removing the outer layer and portions of the underlying layer remaining in the via can be tolerated, the diameter of the backdrilling need not be as large as traditional backdrilling where all layers within the via must be ensured of being completely removed.