Electrical measurement and modeling of co-fired ceramic multi-chip substrates for high speed application

Some of the important electrical properties of cofired ceramic multilayer substrates used for high-speed digital application have been investigated for the purpose of evaluating performance and improving the design process. A test vehicle has been designed to achieve this target. The measurement setup and procedures utilizing time-domain reflectometry techniques are described. Data collected from the test vehicle are summarized and discussed. Computer modeling has been used to help understand the interpret the data, and can be used for future design guidelines. Several cases of crosstalk configuration have been studied. The effect of risetime, line length, and impedance mismatch on the crosstalk was measured and compared with the modeling results. The test vehicle also includes a branched fan-out to simulate most cases of multichip design. The signal propagation delay and distortion have also been measured. Some of the measurement data of a seven-layer RISC (reduced-instruction-set computer) multichip module substrate are presented as a design example