| abstract |
A fabrication method for a metal interconnect having an inner air spacer, applicable to multilevel interconnects technologies, is disclosed. The inner air spacer is formed adjacent to a metal layer to provide a lower dielectric constant in a metal interconnect structure. The inner air spacer is formed by initially forming a dielectric spacer on a sidewall of a second dielectric layer, which sidewall defines a trench opening. The trench opening is then filled with the metal layer. The dielectric spacer is removed to form an air gap between the metal layer and the second dielectric layer. The air gap is sealed off with a portion of a third dielectric layer to form the inner air spacer adjacent to a sidewall of the metal layer. |