A strategy for the selective formation of a pore sealing layer on mesoporous low-k applicable for a Cu dual damascene interconnection process is herein proposed. An ultra-thin, adhesive, and conformal pore sealing layer was formed on mesoporous low-k by spin coating macromolecules. The pore sealant on the Cu surface was selectively decomposed with the help of Cu2O induced oxidization. This selective removal was also examined for patterned structure. Our simple and novel technique will help the integration of ulta-low-k materials in LSI devices.