Constant-Current Stressing of SiCr-Based Thin Film Resistors: Initial "Wearout" Investigation

We have started an investigation of the "wearout" characteristics of our thin film resistors, beginning with two of these processes at the Analog Devices (ADI) Silicon Valley wafer fab. Our goals are (1) to find out what happens to these resistors under accelerated stress and define "failure", (2) to generate better reliability-based design rules as a function of current density, temperature, and resistor geometry, and (3) to compare results between "equivalent" resistor films produced in two of our internal fabs as part of a process transfer. We have characterized the changes in resistance and temperature coefficient of resistivity (TCR) as a result of accelerated to highly accelerated test conditions and determined activation energies for some of these changes