The interfacial fracture energies, Γ, of the Cu/Cr/polyimide system were deduced using X-ray measurement method and theoretical method with variation of Cu film thickness and pretreatment conditions on polyimide surface. The two methods showed reasonably good agreement for most cases, imparting validity of both approaches. Estimated Γ were quite independent of the metal film thickness and increased with the rf plasma power density of polyimide pretreatment as expected. Estimated values of Γ were 46.8±7.8. 170.3±42.9 and 253.9±44.4 J/㎡ for the rf plasma power density of 0.03. 0.036 and 0.05 W/㎠, respectively.