According to the present invention, a process for changing the form of a processed film is performed to planarize it before the processed film which is formed on a wafer is processed in a manufacturing process of a semiconductor device. As the process for changing the form of the processed film, there may be exemplified a single wafer type wet etching process. The compatibility of the processed film with processing means is taken into consideration and, for instance, the wet etching process is applied to the processed film so as to eliminate parts incompatible with the processing means, so that a distribution in-plane of the processed film is previously improved.