| 摘要 |
A light source (1) emits a light beam (6) into a plasma chamber (5) onto a sensor (2), which provides a measurement of the thickness of a film layer depositing on its surface (58) by means of a reflection or re-emission of light through the depositing layer (10) back on a detector (3), which is preferably mounted outside the plasma chamber (5). The arrangement allows an online measurement of the growing thickness of the depositing layer (10) during e.g. plasma CVD- or plasma etching processes in semiconductor manufacturing. Providing a mirror layer (53) with sensor (2) the reflected light intensity can be compared with the incident light beam (6) intensity leading to a thickness determination by means of known absorption or interference curves. Alternatively, activating a fluorescence layer in sensor (2) by incident light beam (6) particularly in its saturation regime, the absorption of the intensity of the re-emitted light also provides a thickness determination of the depositing layer on surface (58) of sensor (2). Comparing the measured intensity with a threshold value the signal for starting a wet clean step can be issued, or the time left until a wet clean is presumed to be necessary can be calculated. |
