A process is provided for the removal of contaminants from a semiconductor device, for example, removing contaminants from pores of an ultra-low k film. In one aspect, a method includes: providing a dielectric layer with contaminant-containing pores and exposing the dielectric layer to a supercritical fluid. The supercritical fluid can dissolve and remove the contaminants. In another aspect, an intermediate semiconductor device structure is provided that contains a dielectric layer with contaminant-containing pores and a supercritical fluid within the pores. In another aspect, a semiconductor device structure with a dielectric layer containing uncontaminated pores is provided.