A method for forming airgaps within an integrated electronic circuit implements a conformal layer and a nanosheet both of boron nitride. The method has advantages for the circuit due to special properties of boron nitride material. In particular, mechanical strength and heat dissipation are increased whereas electro-migration is limited. The method may be applied to the first interconnect layer of the integrated circuit, for reducing additionally capacitive interactions existing between gate electrode structures and source or drain contact structures.