Ansys Employee
Depends on what the via is used for. If it’s a ground via then size doesn't really matter. If it is a signal via top level the via should be as wide as the trace it is attached to but more important is the board stack up the material used and the layer thicknesses as this will define the via impedance. The trace and via impedance should be the same so that the via does not add any reflections back onto the signal trace.