Reverse Pillar--a Self-Aligned and Self-Planarized Metallization Scheme for Submicron Technology

A new concept in multilevel interconnection, called the reverse pillar process, is introduced. Rather than define interconnections in the metal, the reverse pillar process etches trenches in the dielectric with the reverse tone metal mask. A window contact is also etched in the dielectric and can be made self-aligned to the trench. The contacts and trenches are simultaneously filled by a blanket metal deposition. The metal is then etched back to leave it recessed in the trench and filling the contact. The approaches all result in a planarized structure upon which additional processing can be undertaken more easily than in conventional schemes. Films of Al or tungsten are mentioned. 12 ref.--AA(UK).