Method for making air cavities in microstructures, in particular such as interconnection structures with air cavities for an integrated circuit

摘要

The method involves providing a microstructure (10) with a gap filled with a sacrificial material, where the gap is delimited by a non-porous membrane (18). The microstructure is thermally treated at temperature that is less than theta-1 for selectively decomposing a pore-forming agent to making a porous membrane (14). The microstructure is thermally treated at temperature that is equal to theta-1 for decomposing the material and for obtaining extraction of the material from the gap through the porous membrane, so as to obtain air gaps (19, 20) instead of the gap filled with the material.