Mechanically reinforced highly porous low dielectric constant films

Abstract

A porous medium, such as a low dielectric constant film, can be made into an aggregate material to provide increased mechanical strength on a temporary basis. This can be achieved by, for example, a permeable modification treatment of the porous medium. By introduction of a secondary component into the void fraction of the porous medium, the mechanical properties are temporarily improved such that a porous film has mechanical characteristics similar to those of a much stiffer film. Methods in accordance with the present invention permit effective processing of highly porous interlayer dielectric (ILD) materials in a Cu damascene interconnect technology. Once a process operation such as a Cu chemical mechanical polishing (CMP) process, which requires greater mechanical strength than that provided by the porous film alone, is completed, the secondary component can be removed by methods such as displacement or dissolution.