In situ infrared reflection absorption spectroscopy of materials formed on SiO2 at chamber surface in inductively coupled plasma etching of aluminum

In situ infrared reflection absorption (IRA) spectroscopy was used to investigate materials formed on SiO2 film coated on samples mounted on the inner surface of a process chamber for inductively coupled plasma etching of aluminum partially coated with photo-resist. Aluminum wafers partially covered with photo-resist film were etched using BCl3 and Cl-2 plasma generated in a quartz chamber surrounded by an RF coil. Bias RF was applied to the aluminum wafers at the same time. This is the first time that, in order to predict the IRA spectra, the reflectivity of inorganic multilayers formed on metal substrates was calculated using the optical constants of the materials. The experimental spectrum for SiO2 film and materials formed on the SiO2 fam during the 2 mu m-deep etching process were well characterized with the calculated spectrum of a SiO2 film and a B2O3 layer on the SiO2 film, respectively.