Controllable Ultra Low- k by Via-Typed Air Gap with the Better Design Margin for Logic Devices below 45nm Node

By changing the air gap to a via-typed air gap, the height of the air gap is reduced up to about 50% compared to the height of the trench-typed air gap. The controllable (1≤k <2.9) ultra low-k is also easily fabricated by adjusting the space of the via-typed air gap. The via-typed air gap makes the design margin better due to its lower height in the dense and narrow lines.