Fabrication and performance of embedded matrix indium thermal interface materials for advanced FCBGA packaging

• Copper foam (CF) matrix embedded in indium (In) effectively prevents leakage and pump-out of liquid In during multiple reflow cycles in FCBGA packaging, leveraging capillary forces. • The CF matrix promotes the formation of rod-like Cu11In9 at the CF-In interface and inhibits the growth of Ni3In7 IMC at the In-substrate interface, enhancing metallurgical bonding. • The embedded CF matrix improves the shear strength of solder joints by 22.9% and enhances thermal conductivity, while altering fracture behavior from ductile to ductile-brittle mixed type. • This novel TIM1 design eliminates the need for sealants or dams, reducing risks of In explosion and thermal degradation, and avoids additional keep-out zones, offering a more reliable solution for advanced FCBGA packaging.