the concentration of the solvent is preferably reduced to minimum by the soft baking step and thus the soft baking step is performed until the solvent is mostly evaporated and a thin coating layer of photoresist remains on the substrate next the substrate coated with the photoresist layer is selectively exposed to light particularly ultraviolet light using a suitable mask to obtain a desirable pattern the exposed substrate is then dipped into an aqueous alkaline developing solution until either the exposed photoresist layer is all or almost entirely dissolved suitable aqueous developing solution includes an aqueous solution including alkaline hydroxides ammonium hydroxide or tetramethylammonium hydroxide tmah the substrate with the exposed photoresist removed is then taken out from the developing solution the resulting substrate is heat treated to improve and to increase the chemical resistance of the photoresist layer the step is called a hard baking step the hard baking is done at a temperature below the softening point of the photoresist layer preferably at about 100 u00b0 c to 150 u00b0 c the developed substrate is treated with an etchant or with vapor plasma to etch the exposed portion and the remaining photoresist protects the substrate regions which it covers the photoresist layer is removed from the etched substrate using a stripper to complete the pattern onto the substrate surface a photoresist composition including 6 43 wt of a photosensitive chemical 19 47 wt of a polymer resin 70 4 wt of 3 methoxybutyl acetate and 3 70 wt of 4 butylolactone was drop wise applied to 4 inch bare glass plates and the glass plates.