MICROWAVE CHARACTERIZATION OF MICROSTRIP LINES AND SPIRAL INDUCTORS IN MCM-D TECHNOLOGY

The thin film implementation of MCM technology has been proposed as a suitable interconnection medium to support mixed device types, including all silicon CMOS and bipolar IC technologies. A further extension of this concept is the interconnection of GaAs and silicon IC's on the same substrate for applications in the microwave frequency region. As a prelude to the construction of such mixed technology modules, the microwave behavior of the silicon substrate interconnection technology has, therefore, been characterized. The MCM-D technology whose microwave characteristics are described in this paper comprises a four level metallization, aluminum-polyimide structure defined on a silicon substrate. A dedicated microwave characterization layout was designed and implemented which included a series of microstrip lines, spiral inductors, microstrip coupling structures, ring resonators, and microwave calibration structures. Analog measurements of these structures were then carried out using RF-on-wafer (RFOW) methods at frequencies from 0.5 to 20 GHz. Equivalent circuit models were derived which gave a close fit to the experimental measurements and a range of transmission line and spiral inductor components characterized. Useful analog transmission line behavior was indicated for 10-mm line lengths to 10 GHz, while inductors were measured with primary inductances approaching 20 nH with useful Q values in the 1-3 GHz region. Layout rules for low crosstalk were also devised.