Originally designed to interconnect high density MCMs, IBM has been manufacturing PWBs with up to 40 layers for nearly two decades. In addition, as chip
carrier packages migrated to surface mount in the 1980's, higher density PWBs with 5 mil laminate cores and 3 mil lines were developed to accommodate BGA package footprints as low as 1 mm. These designs
include mechanically drilled, blind and buried vias. IBM's expertise in this area offers customers access to high volume production of complex, high layer count, high wiring density cards and boards.
