A semiconductor package and substrate having multi-level plated vias
provide a high density blind via solution at low incremental cost. Via
are half-plated atop a circuit pattern and then a second via half is
added to complete the via after isolation of elements of the circuit
pattern. Successive resist pattern applications and etching are used to
form a via tier atop a circuit pattern that is connected by a thin plane
of metal. After the tier is deposited, the thin metal plane is etched to
isolate the circuit pattern elements. Dielectric is then deposited and
the top half of the via is deposited over the tier. The tier may have a
larger or smaller diameter with respect to the other half of the via, so
that the via halves may be properly registered. Tin plating may also be
used to control the etching process to provide etching control.