Aromatic Polyimide Resins for High Density Packaging Substrates

Molecular weight-controlled aromatic polyimide resins for fabrication of high density IC packaging substrates have been developed. The aromatic polyimide resins showed good laminate processability, which could easily dissolve in organic solvent to give low viscosity solution for impregnation of E-glass fiber cloths. After completely removal of the organic volatile, the polyimide/glass fiber (PI/GF) cloth prepreg could be plied up and then thermally cured at 280degC to give the PI/GF laminate suitable as packaging substrate core. Experimental results indicated that the polyimide laminates have the desirable characteristics for packaging substrate core, including 1) excellent thermal stability with initial thermal decomposition temperature of >500degC, CLE(in-plane) of 15-19 ppm/degC and glass transition temperature of >220degC; 2) good mechanical properties with flexural strength of >430 Ma and flexural modulus of 20 GPa, tensile strength of >230 MPa and impact toughness of 84 kJ/m²; 3) great electrical insulating and dielectric properties with volume resistivity of >1016 Omegaldrcm, dielectric constant of 4.1 and dissipation factor of 0.005 etc.; and 4) high peel strength of copper foil to laminate in Cu-claded laminate (>1.5N/mm).