How to Design Half (Castellated) Holes for PCB | PCBfast

At PCBfast, we follow strict manufacturing standards to ensure the accuracy and reliability of half-hole (castellated) designs. Please note the following design requirements, which apply to the copper layer, solder mask layer, and drilling layer:

•  The copper layer must retain pads, and the solder mask layer should have corresponding openings.

•  Plated through holes that extend beyond the board edge are regarded as half-holes (regular vias are not included).

•  The hole diameter should be ≥ 0.4 mm, and the spacing between holes should be ≥ 0.4 mm.

For specific size references, please refer to the chart below and our design examples for correct half-hole layouts.