Third,many new in terfaces are in troduced in the system.The Material A forms interfaces with the Material B on two sides, EAC ceramic on the third side, and core on the fourth side. Both material A and material B are epoxy based polymers with proprietary additives with different silica filler % to provide the required stiffness. The typical filler % in Material A is about 1.3×to 1.5×that of Material B. The EAC is expected to expandnegligiblyinthethickness(Z)directionwhencompared to the EAC cavity material and the core at reflow temperature. This difference will be directly reflected into the warpage of the C4 area—impacting the first level interconnect (FLI) joint formation process. Lastly, the risk of ceramic cracks during the high pressure of the substrate BU process cannot bediscounted