Electrical characterization of the interconnected mesh power system (IMPS) MCM topology

A significant decrease in MCM substrate production cost can be achieved by reducing the number of substrate layers from the conventional four or five (power, ground, X signal, Y signal, pad) to two or three. Besides reducing direct processing steps, yield will also increase as defect producing operations are eliminated. This paper describes the Interconnected Mesh Power System (IMPS), a new interconnection topology which leverages the production technologies of fine line lithography and batch via generation to allow planar power and ground distribution, and dense signal interconnection, on only two metal layers. Several possible implementations of the topology in MCM-D and MCM-L are described. The design of a test vehicle which characterizes both the signal transmission and power distribution properties of the IMPS topology is discussed. The test vehicle has been built in an aluminum/polyimide on silicon process developed at HiDEC. Results of signal transmission measurements (impedance, delay, and crosstalk) for various signal/power/ground configurations are presented. Power distribution characteristics (DC drops and AC noise) are presented and compared with measurements on a test vehicle implemented with solid power and ground planes. From the measured characteristics of the test vehicle, the applicability (clock frequency, power, etc.) for the IMPS topology has been determined. Most MCM applications can benefit from the substrate cost reduction enabled by IMPS