Postfabrication independent inductance and quality factor adjustments of on-chip inductors by above-CMOS processing for rapid prototyping of radio frequency system on chips

The flexible adjustment of on-chip inductor characteristics after a regular complementary metal-oxide-semiconductor (CMOS) fabrication was realized by the "above-CMOS" processing technology for radio frequency (RF) system-on-a-chip (SoC) rapid prototyping. It is shown that the above-CMOS metal pattern formation in a chip-by-chip manner can both increase and decrease the inductance (L) values of on-chip inductors. It is realized by applying various planar patterns of a metal layer deposited on the passivation layer of the chip. To increase the modification range of the characteristics and to establish an independent L and quality factor (Q) adjustment scheme, we have newly developed a pre-design method and a Q-compensation method. By combining these methods, the effective L and Q values of the on-chip inductors can be independently and arbitrarily modified. The adjustment of the input impedance matching frequency of a low-noise amplifier (LNA) using this scheme has also been demonstrated.