PURPOSE: To control the finished dimensions of circuit patterns of the upper and lower parts of a step on a foundation simultaneously by a method wherein the film thicknesses are determined corresponding to the point at which the respective periodical variation curves of the sensitivities of the upper and lower parts of the step are in parallel or approximately in parallel with each other and the resist films are developed by using a specific terminal point detection method.

CONSTITUTION: The thicknesses of resist films applied to the upper and lower parts of a step part are determined corresponding to a point A where the sensitivity curves obtained by measuring the resist sensitivities while the film thicknesses are varied have the same tendency. A filter whose reflectance for a reflected light from the upper part of the step is the maximum is selected and a light is applied to a foundation 13 through the resist 14 and the reflected light is detected. The period of a protrusion and a recess produced in accordance with the progress of development corresponds to the development of λ/2n of the resist film thickness, wherein λ denotes the wavelength of the observed light and (n) denotes the refractive index of the resist 14. At the time of C, λ/4n of the thickness of the resist 14 is left. This time C corresponding to the minimum critical point is detected and a total development time is determined as a first or second degree function of the time. With this constitution, even if the formed regions are different, the stable finished dimensions can be obtained.