In-situ infrared absorption techniques have been used to examine fundamental chemical and physical phenomena in semiconductor process plasmas. Fourier Transform infrared absorption spectroscopy (FTIR) is used to characterize the chemical environment in halocarbon containing plasmas which produce particles. A correlation is observed between the distribution of chemical species in the plasma and the extent of particle formation as demonstrated by laser light scattering. The addition of oxygen affects both the chemical species distribution and the amount of light scattering in the plasma. Also, high resolution infrared laser absorption spectroscopy is used to characterize rotational and vibrational temperatures in a parallel-plate N20 discharge. The relevance of these studies to semiconductor process plasmas is also discussed.
James A. O'Neill,
"Infrared diagnostics for semiconductor process monitoring", Proc. SPIE 1594, Process Module Metrology, Control and Clustering, (1 January 1992); doi: 10.1117/12.56649; http://dx.doi.org/10.1117/12.56649