METHOD OF MANUFACTURING A SUBSTRATE, HAVING A POROUS DIELECTRIC LAYER AND AIR GAPS, AND A SUBSTRATE

摘要

A method to produce air gaps between metal lines (8(i)(and within dielectrics. The method consists of obtaining a dual damascene structure, applying a diffusion barrier layer (10) directly on the planarized surface and performing a lithography step, thus shielding the metal lines underneath the diffusion barrier layer. Optionally, some portions of large dielectric areas (6) between the metal lines (8(i)) are also shielded. The exposed diffusion barrier layer portions and underlying dielectric are etched. A layer of a material that can be decomposed in volatile components by heating to a temperature of typically between 150-450°C is applied and planarized by etching or CMP. A dielectric layer (20) that is permeable to the decomposition products is deposited and subsequently the substrate is heated. Then, the disposable layer decomposes and disappears through the permeable dielectric layer, leaving air gaps (22) behind in between the metal lines (8(i)) and the large dielectric areas.