The disclosure relates to methods of forming organic polymers comprising polyimide and layers comprising the same and to methods of reducing polyamic acid content of an organic polymer. The embodiments of the disclosure further relate to methods of fabricating semiconductor devices, to selectively depositing a material on a surface of a semiconductor substrate and to semiconductor processing assemblies. The methods are characterized by contacting a polyimide-containing material, such as a layer, with a modifying agent that increases the proportion of polyimide in the organic polymer material.