Film thickness measuring device, film forming system, and film thickness measuring method

A film thickness measuring method comprising:

• providing a film thickness measuring device including:
• a stage configured to dispose a substrate thereon;
• a light emitter/receiver configured to emit light for measuring a film thickness to the substrate disposed on the stage and receive a reflected light from the substrate disposed on the stage;
• a distance meter configured to measure a distance between the light emitter/receiver and the substrate and an elevator configured to move the stage up and down;
• a rotation driver configured to rotate the stage;
• an orientation detector configured to detect an orientation of the stage;
• and
• a controller configured to control an overall operation of the film thickness measuring device;
• forming, by the orientation detector, a light transmission and non-transmission pattern by a slit shape formed on a rotating plate connected to a rotation shaft of the rotation driver;
• detecting a rotation angle, as the orientation of the stage, from an arbitrary reference point of the rotation shaft of the rotation driver based on the light transmission and non-transmission pattern, by the orientation detector;
• detecting, by the orientation detector, an orientation of the stage when the substrate is disposed on the stage, based on the rotation angle of a support shaft connected to the stage;
• rotating, by the rotation driver, the stage based on a detection result of the orientation of the stage such that the orientation of the stage becomes a desired orientation when the substrate is disposed thereon;
• disposing the substrate on the stage having the desired orientation;
• and
• emitting the light from the light emitter/receiver and measuring a thickness of the film formed on the substrate based on a light receiving result of the reflected light of the light emitter/receiver, by the controller.