in a given mass range across the collector and records the resulting spectrum although generally shown in fig2 the real time control system can be applied to ald and cvd processes among others fig3 is a graph showing an exemplary relationship between the feeding concentration of ozone and the intensity of ethane generated in an atomic layer deposition process according to one embodiment of the present invention when performing an ald process on alumina al 2 o 3 using trimethylaluminum tma al ch 3 3 and ozone o 3 the following reaction occurs the thickness of an alumina film deposited on the wafer in units of atoms based on the above reaction is proportional to the amount of ethane c 2 h 6 that is a resulting gas thus the thickness of the alumina film can be monitored in real time by the amount of ethane generated after reaction it can be ascertained from fig3 that the intensity of ethane measured by qms proportionally increases as an ozone feeding concentration increases based on the measurement result the controller 50 of fig2 can determine whether the reaction or processing gases of the reaction or processing gas supplying portion 20 are to be supplied or not by real time monitoring the intensity of ethane resulting from the ald process performed on alumina fig4 is a time chart of the ald process according to one embodiment of the present invention referring to fig2 4 and 5 a process of real time controlling the ald process according to one embodiment of the present invention will now be described first the wafer 14 is loaded into the deposition chamber 10 maintained at a constant.