Introduction of low-dielectric constant (k) materials, replacing silicon dioxide, has reduced the time delay (RC delay) and enhanced the performance of integrated circuits (IC) significantly. The two most common ways of depositing these low-k materials are spin-on and chemical vapor deposition. Chemical-vapor-deposited low-k materials use an organic precursor consisting of carbon, hydrogen, and oxygen as the main constituents. Some of these precursors yield a significantly large fluorescence signal when irradiated with an appropriate laser. This signal can be successfully utilized to detect the transition from the barrier layer to dielectric layer in chemical mechanical polishing, which is now typically done using reflectivity measurements in the industry. In this work, sensitivity of the fluorescence technique in detecting the transition is demonstrated and compared with the conventional reflectivity method. An abrasion cell integrated with a spectrometer was used to make the measurements. Capabilities and limitations of the fluorescence techniques are discussed.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry