Deep-UV sensitivity of xerogel thin films prepared from solutions of modified titanium alkoxides

Xerogel thin films were prepared from solution of titanium alkoxides (Ti(OiPr)₄) complexed with methacrylic acid (MAA) with different molar ratios. The impact of this parameter on their sensitivity to deep-ultraviolet (DUV) was studied. The chemical modifications were characterized by FTIR spectroscopy in ATR mode, and the optical characterization was done by spectroscopic ellipsometry. In this report, condensation of Ti precursor is induced by exposure to DUV which was demonstrated to be less efficient for low MAA:Ti ratios due to lower substitution degrees. More importantly, the chemical resistance to solvent of thin films can be tuned, which is crucial for photolithography applications. To illustrate this, DUV lithography was performed on thin films for two different MAA:Ti ratios and developed with cyclohexanone and ethanol, giving rise to opposite results. Finally, microstructures by DUV were achieved for solutions with the lowest protection degree. Graphical abstract: [Figure not available: see fulltext.]