SPIRAL INDUCTORS AND TRANSMISSION-LINES IN SILICON TECHNOLOGY USING COPPER-DAMASCENE INTERCONNECTS AND LOW-LOSS SUBSTRATES

Spiral inductors and different types of transmission lines are fabrica ted by using copper (Cu)-damascene interconnects and high-resistivity silicon (HRS) or sapphire substrates. The fabrication process is compa tible with the concepts of silicon device fabrication, Spiral inductor s with 1.4-nH inductance have quality factors (Q) of 30 at 5.2 GHz and 40 at 5.8 GHz for the HRS and the sapphire substrates, respectively. 80-nH inductors have Q's as high as 13, The transmission-line losses a re near 4 dB/cm at 10 GHz for microstrips, inverted microstrips, and c oplanar lines, which are sufficiently small for maximum line lengths w ithin typical silicon-chip areas, This paper shows that inductors with high Q's for lumped-element designs in the 1-10-GHz range and transmi ssion lines with low losses for distributed-element designs beyond 10 GHz can be made available with the proposed adjustments to commercial silicon technology.