A semiconductor device has a first substrate and a second substrate or interconnect substrate with an interconnect structure formed between the first substrate and second substrate or interconnect substrate using a VFM signal, in combination with heat and/or pressure. The interconnect structure can be a bump or a bump with conductive pillars. A microwave source disposed in proximity to the first and second substrates generates the VFM signal. Heat and pressure can be applied to the interconnect structure while using the VFM signal. Heat or pressure can be applied to the interconnect structure while using the VFM signal. A non-conductive film can be formed around the interconnect structure between the first substrate and second substrate. An epoxy and flux material can be formed around the interconnect structure between the first substrate and second substrate.