The application provides a thick film positive
photoresist composition, a preparation method and application thereof. The thick film positive
photoresist composition comprises 70-90 parts of a base resin, 10-30 parts of a photosensitive compound and 100-150 parts of a
solvent A; the base resin comprises a
benzophenone modified phenolic resin and optionally an unmodified phenolic resin; the
mass percentage of
benzophenone groups in the base resin is 0.8-7.5% based on 100% of the
mass percentage of the base resin; the photosensitive compound comprises a non-
benzophenone photosensitive compound and optionally a benzophenone compound; the
mass percentage of the benzophenone compound is less than or equal to 3.0% based on 100% of the mass percentage of the photosensitive compound. The application improves the uniformity of the benzophenone structure in the thick film positive
photoresist composition by designing the specific composition of the thick film positive photoresist composition, thereby improving the steepness of the photoresist and realizing the development of the pattern.