Fault isolation and performance characterization of high speed digital multichip modules

This paper describes two methods for testing high performance digital multichip modules (MCMs). The first technique provides a method for multiplexing automatic test system channels so that clock and data rates can be extended beyond the normal frequency limits of the Automatic Test Equipment (ATE). The multiplexing method has been successfully applied at rates up to 1.6 GHz using 200 MHz ATE. The second approach utilizes an electron beam probe system operating in the voltage contrast mode to measure electrical signals within the MCM. The e-beam probe can be used to supplement scan-based techniques for isolating faults. It can also be used for characterizing signal quality (rise-time, overshoot, crosstalk, reflections) and measurement of relative delays in high performance MCMs.