A method includes performing an etching process in a first process module, moving a workpiece formed by the etching process from the first process module to a second process module, and performing a film forming process on the workpiece in the second process module. In the performing the film forming process, an insulating film is formed on a first surface and a second surface of a laminated portion by plasma of a processing gas that contains hydrogen. In the performing the film forming process, an internal pressure of the second process module is 200 mTorr or more, and a hydrogen partial pressure of the second process module is 15 mTorr or less. The performing the etching process, the moving the workpiece, and the performing the film forming process are consistently performed in a state where oxygen is exhausted.