On-chip high-Q spiral Cu inductors embedded in wafer-level chip-scale package for silicon RF application

On-chip high-Q spiral inductors on Si substrate with thick resin layer have been fabricated. These inductors were fabricated by a thick Cu electroplated rerouting and separated more than 10 /spl mu/m from Si substrate by a thick resin layer. The inductance L of 5.2 and 4.9 nH with a quality factor Q of 18.1 and 27.5 were obtained for a 3.5 turn rectangle spiral inductor at 2 GHz in /spl rho/ of 4-6, 1k /spl Omega/cm, respectively. This technology is favorable for Si RF application to minimize the stray inductance from wire-bonding and reducing circuit resistance.