Abstract: Adherent matrix layers such as post-etch and other post-process residues are removed from a substrate by exposing them to a vapor phase solvent to allow penetration of the vapor phase solvent into the adherent matrix layers and condensing the vapor phase solvent into the adherent matrix layers and revaporized to promote fragmentation of the matrix and facilitate removal. Megasonic energy may be transmitted via a transmission member to the adherent matrix through the solvent condensed thereon to loosen fragments and particles. The substrate is typically rotated to improve contact between the megasonic energy transmission member and the condensed solvent and achieve more uniform cleaning. A co-solvent which is soluble in the vapor phase solvent may be added to enhance removal of specific adherent matrix materials.