A method for etching a thin film and fabricating a semiconductor device includes etching the thin film on a substrate, while monitoring the removal of an endpoint detection layer remotely located from the substrate, such that precise control of the thin film etching is provided by monitoring the removal of the endpoint detection layer. The endpoint detection layer is formed on a surface of an etching apparatus that is exposed to the same etching conditions as the thin film to be etched. The etching of the thin film is stopped when a predetermined amount of the endpoint detection layer has removed from the surface of the etching apparatus.