IR-Fourier Spectroscopy of Attenuated Total Reflection of Polyimide Films on Monocrystalline Silicon Wafers

Abstract

The spectra of attenuated total reflection of polyimide PI-2610 films deposited on single-crystal silicon wafers by centrifugation are studied. The films were irradiated by electrons with energy of 5 MeV on a linear electron accelerator at doses of 1 · 10¹⁴–2 · 10¹⁵ cm^–2. The most intense in the spectrum of PI-2610 polyimide films are the C-N-C_st vibration bands of the imide ring (1349 cm^–1), aromatic ring vibrations (1517 cm^–1), C=O_str stretching vibrations of the imide ring group (1700 cm^–1), and stretching vibrations of C-C bonds in the CO-C_st group (1074 cm^–1), as well as bands of bending vibrations of C-H bonds with maxima at 734 and 828 cm^–1. At an initial dose of 1 · 10¹⁴ cm^–2, a change in the spectral shape and intensity of the bands with maxima at 1700 and 1349 cm^–1, caused by vibrations of the C=0 and C=N-C_str groups, was observed. It is assumed that this is due to the relaxation of the metastable states of these groups. At a dose of 2 · 10¹⁵ cm^–2,  a decrease in the intensity of bands caused by asymmetric and symmetric stretching vibrations of C-H₂ bonds was detected. The intensity of the ATR bands caused by vibrations of C=O and C-N bonds, aromatic and imide rings remained practically unchanged.