New Hope for Ultralow-k Integration

摘要

The semiconductor industry is keen to reduce RC time delays, and one of the most effective ways to do that is to move to dielectrics with lower dielectric constants. SiO_2 has a k value of 4.1, fluoricated silicate glass has a k value of 3.1 and newer carbon-doped oxides have a k value of 2.9-3.0. Most 65 nm interconnect technologies announced to date employ carbon-doped oxides, but there is a huge perform- ance benefit in going to even lower k values. The International Technology Roadmap for Semiconductors (ITRS) has a target for effective k values (k_(eff)) of 2.3-2.6 for the 45 nm node, 2.0-2.4 for the 32 nm node and < 2.0 for the 22 nm node (k_(eff) is defined as the k value after the materials are integrated/processed). The lowest k value achievable is 1.0, which is that of air.