METHOD FOR CONTROLLING THICKNESS OF THIN FILM IN THIN FILM FORMING PROCESS FOR SEMICONDUCTOR SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To reduce the thickness deviations of thin films in a reaction furnace by calculating the process temperature which gives an influence on the calculated representative thickness of the thin films from a correction formula, and executing a thin film forming process by using a corrected deposition time and the corrected process temperature. SOLUTION: The central area 210 of a reaction furnace in which the average thickness of thin films becomes closest to a target film thickness is defined as a reference area. The deposition time (DT) of the thin films is calculated from a formula, DT(n+1)=DT(n)+(target thin film thickness-average thin film thickness)/time gain rate, so that the average thickness in the reference area may become the target thickness. This is for correcting the thicknesses of the thin films by the DT in the reference area and by the process temperature in the other area. Therefore, the corrected process temperatures of an upper area 240 and lower area 250 in which monitoring wafers are placed in the reaction furnace are calculated and the corrected process temperature of a central lower area 230 is successively calculated. For this correction, the representative thicknesses of the thin films in the areas can be calculated by using a prescribed table.