Emerging nanoelectronics are been hindered by reliability challenges such as stress related failures. The stress buildup is due primarily to mismatch in the coefficient of thermal expansion (CTE) of the materials of construction which results in the generation of defects such as cracks, voids, delamination, plastic deformation, substrate warping and buckling. These types of damage ultimately lead to open or short circuits in the devices, resulting in catastrophic failure.  The chemistry and physics of the materials also play crucial roles in the changes in the stress over time, especially in low operating voltage devices. The process flows of such low voltages devices entail low temperatures processing, and the use of low temperature deposited dielectrics, such as low-k materials, plasma deposited and sub-atmospheric pressure deposited films derived from organometallic precursors as insulators between metal lines and layers. Unfortunately, these low-temperature-processed materials are metastable due the presence of reactive metastable intermediates from the cracking of the precursors, and incomplete reactions within the films that result in electrically active defects in the “as deposited” films. Metrology is thus needed for the accurate quantification of the reliability impact of stress evolution in such integrated systems.  Unfortunately, traditional spectroscopic tools, such as infra-red (FTIR), ellipsometry, electron spin resonance (ESR), solid state nuclear magnetic resonance (NMR), XRD, etc. which do not accommodate integrated devices.  Microwave (RF)-based metrology tools are uniquely suitable for studying the buried structures and interfaces inherent in such nanoelectronic devices.

In this paper, we discuss the use of broadband radio waves (RF) (with frequencies up to 20 GHz) to detect, characterize and monitor the evolution of active defect in low-temperature processed dielectric films as a result of deliberate thermal exposure.  The impact of thermal anneal on the behavior of the electrical defects shed light on the chemical changes occurring within the dielectric films that lead to changes in stress buildup.