Integrated circuit package having coaxial pins

An integrated circuit package including a multilayer ceramic substrate for mounting a plurality of integrated circuit chips on a first surface thereof. The substrate is provided with a power supply layer, a ground connection layer and circuit patterns. An array of coaxial pins is juxtaposed on the opposite surface of the substrate. Each coaxial pin includes an inner conductor and an outer conductor. The inner conductor of one or more coaxial pins is connected to the power supply layer and the inner conductors of the remaining coaxial pins are connected to the circuit patterns. The outer conductors of all the coaxial pins are connected to the ground connection layer.