  This paper analyzes a transient method for the characterization of
low-resistance thermal interfaces of microelectronic packages. The transient
method can yield additional information about the package not available with
traditional static methods at the cost of greater numerical complexity,
hardware requirements, and sensitivity to noise. While the method is
established for package-level thermal analysis of mounted and assembled parts,
its ability to measure the relatively minor thermal impedance of thin thermal
interface material (TIM) layers has not yet been fully studied. We combine the
transient thermal test with displacement measurements of the bond line
thickness to fully characterize the interface.
