AZ nLOF series photoresist films on monocrystalline silicon

Films of negative photoresists (FR) AZ nLOF 2020, AZ nLOF 2070 and AZ nLOF 5510 with a thickness of 0.99–6.0 microns deposited on the surface of silicon wafers by centrifugation have been studied by the methods of microindentation and IR Fourier spectroscopy using a diffuse reflection module. It has been established that FR films behave like elastoplastic materials in which tensile elastic stresses are present. The most intense in the reflective absorption spectra of AZ nLOF photoresistive films are bands of valence vibrations of the aromatic ring (≈ 1500 cm–1), pulsation vibrations of the aromatic ring carbon skeleton (double maximum ≈ 1595 and 1610 cm–1), a wide structured band with several maxima in the range of 1050–1270 cm–1 and a band with a maximum of ≈ 1430 cm–1 due to vibrations of the benzene ring, associated with the CH2 bridge. It is shown that the line corresponding to the vibrations of the CH3 groups with a maximum at 2945 cm–1 is caused by the solvent. The differences in the FR spectra of AZ nLOF 2020 and AZ nLOF 2070 are associated with the presence of a residual solvent in the films and the interaction of its molecules with the aromatic rings of the main FR component – phenol-formaldehyde.