Direct patterning ITO transparent conductive coatings

A low cost sol–gel process to directly prepare patterned ITO thin films has been developed by Chemat Technology, Inc. This technique eliminates the photolithography process. ITO polymeric precursors were prepared by modification of indium isopropoxide and tin isopropoxide followed by hydrolysis and polycondensation. The polymers were applied onto glass substrates either by dip coating or by spin coating. The ITO polymer films were then patterned by covering with a photomask, exposed to UV irradiation, and developed in an organic solvent. After sintering in air and annealing in an inert atmosphere, the patterned ITO films have a sheet resistance of <25 Ω/□ and a transmittance of >90%. The ITO coatings were also found to have very good chemical and mechanical properties.