Film forming method and film forming apparatus

A film forming apparatus comprising:

• a processing container in which a substrate having a base film formed thereon is accommodated;
• a processing gas supply mechanism configured to supply a tungsten chloride gas and a reducing gas for reducing the tungsten chloride gas into the processing container;
• and
• a controller,
• wherein the controller is configured to execute:
• an etching step of etching a portion of the base film to reduce a film thickness of the base film by intermittently supplying the tungsten chloride gas into the processing container while performing a purging step in the course of the intermittent supply of the tungsten chloride gas;
• and
• a film forming step of forming a tungsten film on the base film by alternately supplying the tungsten chloride gas and the reducing gas for reducing the tungsten chloride gas into the processing container while performing the purging step in the course of the alternate supply of the tungsten chloride gas and the reducing gas.