Embedded Die Substrate is directly embedding semiconductor dies within substrate material creating integrated multi-chip modules — maximizes density. Die Placement cavity within substrate; die glued in place. Interconnection bondwires or flip-chip bumps from die pads to substrate traces. Trace Routing multiple metal layers route signals around embedded dies. Vias connect metal layers; thermal vias dissipate heat. Encapsulation potting or overmolding protects. Thermal die coupled to substrate; heat dissipates efficiently. Multi-Chip multiple dies embedded simultaneously or sequentially. Sequential embed tier, add layer, embed next (3D-like). Cost embedding adds steps but justified for high-density. Yield defective embedded die: entire substrate often scrapped. Manufacturing precise cavity depth, placement alignment, encapsulation. Interconnect shorter than separate components. CTE Stress mismatch between materials (substrate, epoxy, silicon) creates stress. Reliability thermal cycling tests validate design. Design layout complex; critical traces avoid die. Warpage large substrate warping affects yield. Applications high-density modules, automotive, medical. Embedded die substrates achieve extreme density via monolithic integration.