Lithographically defined vertical interconnect access (via) for a bridge die first level interconnect (fli)

Abstract

Embodiments described herein relate to lithographically defined vertical interconnect accesses (litho-vias) for a bridge die first level interconnect (FLI) and techniques of fabricating such litho-vias. In one example, a package substrate comprises a bridge die embedded in the package substrate; a first contact pad outside a perimeter of the bridge die; a second contact pad inside the perimeter of the bridge die and coupled to the bridge die by a first via; a third pad inside the perimeter of the bridge die, adjacent to the second contact pad, and coupled to the bridge die by a second via. The first contact pad has a surface finish disposed thereon. A first protruded interconnect structure is positioned on the first via and a second protruded interconnect structure is positioned on the second via. Each of the first and second vias have sidewalls that are substantially vertical.