High temperature superconductor packaging technology

The objective of using high-temperature superconductor (HTSC) interconnects in multichip module (MCM) substrates is to increase the functional performance to volume ratio above that of conventional MCMs. Functional performance is increased through the use of superconductive interconnect traces which allow ultra-high-speed transmissions between devices. Determining the exact operational characteristics of both the HTSC interconnect and the CMOS devices in a cryogenic environment is the initial requirement in building a HTSC MCM. Once they have been established, demonstration prototypes of the HTSC MCMs can begin to be built and tested. HTSC material requires an extremely cold (less than -150 degrees C) cryogenic environment to become operational. This produces a unique challenge for the package design. The package must allow the flow of a cryogen through it, address electrical I/O, testability, and reliability, and survive many radically large temperature changes. Special attention to the coefficient of thermal expansion of the constituent materials is required to produce a consistently reliable design.<>