Thin film etching method and semiconductor device fabrication using same

A method for etching a thin film, the method comprising:

• providing a plasma etching apparatus having a process chamber equipped with an optical endpoint detection device;
• forming an optical layer on at least a portion of the process chamber;
• placing a device substrate having the thin film thereon in the process chamber and etching the thin film, while monitoring the optical layer with the endpoint detection device;
• and
• terminating the etching upon command from the endpoint detection device.

A method for fabricating a semiconductor device, the method comprising:

• forming a gate electrode on a gate dielectric layer overlying a substrate;
• forming a spacer material on the gate electrode;
• and
• placing the substrate in an etching chamber and etching the spacer material using an etching process to form sidewall spacers on sidewalls of gate electrode,
• wherein an endpoint of the etching process is determined by monitoring the removal of a material layer from a surface of the etching chamber.

A method for controlling the etching a thin film having a predetermined thickness, the method comprising:

• forming an endpoint detection layer on at least a portion of an inner surface of a plasma etching apparatus,
• wherein a thickness of the endpoint detection layer is correlated with the predetermined thickness of the thin film;
• etching the thin film and the endpoint detection layer in the plasma etching apparatus, while monitoring the endpoint detection layer;
• and
• stopping the etching when a predetermined amount of the endpoint detection layer has been removed.