Low capacitance approaches for 22nm generation Cu interconnect
Various integration approaches, including homogeneous porous Low-k and air gaps, for low-capacitance solution were investigated for 22 nm Cu interconnect technology and beyond. For homogeneous Low-k approach, K=2.0 Low-k material is successfully integrated with Cu. Up to 15% line to line capacitance reduction compared with LK-1 (K= 2.5) was demonstrated by a damage-less etching and CMP process. For air gap approach, a cost-effective and Selective air gaps formation process was developed. Air gaps are selectively formed only at narrow spacing between conduction lines without additional processes. authors: T.I. Bao, H.C. Chen, C.J. Lee, H.H. Lu, S.L. Shue, C.H. Yu
Interconnect
On-chip Interconnect
On-chip interconnect today is based on copper/low-k wiring – in today’s chips, there can be more than 100 km of copper wires.
TSMC’s leading edge technologies use a novel copper gap-fill solution to enable the fabrication of smaller conductor lines. Newly-developed materials and processes allow significant reduction in line and via resistance to improve chip performance. A comprehensive suite of innovations on integration scheme, low-k material, and low-k process with selective deposition further enhance both performance (through capacitance reduction) and reliability. Beyond copper interconnect, explorations of single metallic elements, binary and ternary alloys, and 2D materials for future interconnect materials are underway both within TSMC and with our academic partners.
