a dual damascene process is disclosed , in which a contact via and trench pattern is etched into insulating layer . the via is first partially filled by selective metal deposition , thereby forming a partial plug that raises the floor and reduces the effective aspect ratio of the trench and via structure . the remaining portion of the contact via is then filled with a more conductive material . this deposition also at least partially fills the overlying trench to form metal runners . in the illustrated embodiment , hot aluminum deposition fills the portion of the contact via left unoccupied by the selective deposition and overfills into the trench . a further , cold aluminum deposition then follows , topping off the trench prior to planarization . the dual damascene structure thus exhibits a raised floor relative to conventional dual damascene metallization , while still retaining the conduction benefits of aluminum through a significant portion of the contact and the metal runner formed in the trench .