This paper describes a high-speed multichip (3232 space-division) switching module for high-definition TV broadcasting and switching systems. This newly developed module employs new Si-bipolar SST switching LSIs and a multi-layer substrate with a polyimide dielectric and a fine pattern of copper conductors. This substrate contains matrix-shaped thin film registers for terminated transmission and a spiral via hole structure to increase fabrication reliability. The module has 50 ohm characteristic impedance transmission lines with a deviation of less than 2.5%. The multichip module can handle a signal speed of 1.8 Gb/s using 1 : 1 and 1 : n connections. This technology allows a dramatic reduction in module size to 1/20 of that possible with conventional surface-mounted techniques.