Abstract: A high density interconnect (HDI) structure having a dielectric multi-layer interconnect structure on a substrate is fabricated by forming a chip well, placing a chip in the well, and connecting the chip to the interconnect structure. Additionally, temperature sensitive chips or devices may be located beneath the dielectric multi-layer interconnect structure. A spacer die may be located in the substrate while the interconnect structure is fabricated and removed after a chip well aligned with the spacer die is formed, in order to accommodate a chip thickness which is greater than the dielectric multi-layer interconnect structure thickness.