Analysis of heretofor unsolved electromagnetic simulation problems in high performance multichip modules and printed circuit boards: simulation and measurement of power plane noise and internal inductance

As digital system clock rates have increased and risetimes have decreased, simple RC load delay calculations have proved inadequate for prediction of signal propagation on circuit boards, MCMs, and even high performance integrated circuits. Issues such as characteristic impedance, proper termination, crosstalk, and dispersion dominate interconnect design, have to be dealt with. Electromagnetic (EM) modeling in high performance systems has become an integral part of the design process. Specialized EM modeling tools are required to address the problems of high clock rate digital system design. Development of these specialized EM simulation tools requires extensive analysis of algorithms and their numerical implementation, to ensure that the appropriate electromagnetic effects are modeled in an efficient manner. The algorithms, mathematics, and implementations of EM simulation programs must be verified through a process of design, assembly, and testing of specialized physical structures. Two new algorithms are described from derivation through measurement and verification: accurate analysis of resistance and inductance for MCM interconnect; and equivalent models of power and ground plant noise both of these new algorithms require measurement data to verify their accuracy. In the case of inductance modeling for MCM interconnect, it was possible to utilize existing transmission line test structures, but new test techniques were used to precisely measure impedance over a range of frequencies. In the case of the power and ground plane model, a unique test vehicle was designed specifically to verify both the circuit and wave models, using a variety of time and frequency domain measurement techniques.<>