A releasable buried layer for 3-D fabrication and methods of manufacturing is disclosed. The method includes forming an interposer structure which includes forming a carbon rich dielectric releasable layer over a wafer. The method further includes forming back end of the line (BEOL) layers over the carbon rich dielectric layer, including wiring layers and solder bumps. The method further includes bonding the solder bumps to a substrate using flip chip processes. The flip chip processes comprises reflowing the solder bumps and rapidly cooling down the solder bumps which releases the carbon rich dielectric releasable layer from the wafer.