| 摘要 |
The present invention provides apparatus for controlling the operation of plasma etching a semiconductor substrate by an alternating etching method, the apparatus comprising: a process chamber (1) in which said substrate (2) is processed, means for generating a plasma (6); at least one first window (7) formed in a first wall (8) of said chamber (1) facing the surface (2a) to be etched of said substrate (2); at least one second window (10) formed in a second wall (11) of said chamber (1) lying in a plane different from said first wall (8); first means (18) coupled to said second window (10) to detect a light signal (17) relating to a selected wavelength emitted by said plasma (6); means (13, 15) for emitting a monochromatic light signal (14) through said first window (7) towards said surface (2a) in a direction (9) substantially perpendicular to said surface (2a) in such a manner that said incident signal (14a) is reflected on said surface (2a); second means (16) for detecting said reflected signal (14b); and transformation means (19) coupled to said first means (18) and to said second means (16) to transform the signal detected by said second means (16) as a function of the signal detected by said first means (18).
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