FORMATION OF RESIST PATTERN

PURPOSE:To improve subsurface treating and line width controlling properties by treating the deposits on side walls generated at the time of dry development of a photoresist with plasma contg. fluorine or acidic soln. CONSTITUTION:The prescribed parts of the photoresist film 3 are exposed via a mask pattern 17 by a UV beam 16 to form exposed parts 4a. Silicon is then selectively diffused into the exposed parts 4a in a gas contg. silicon in the molecule of hexamethyl disilazane, etc. The resist film is thereafter subjected to a dry development by O2 plasma to remove the exposed parts. The deposits of 200 to 400Angstrom are formed on the side walls of the resist film 6 in this state and, therefore, the resist film is immersed into an aq. soln. mixture composed of 90% ammonium fluoride and 40% acetic acid to remove the deposits in succession to the above-mentioned development. The controllability of the line width transferred on the subsurface side walls and the reproducibility of the subsurface working are improved in this way.