| 摘要 |
In order to monitor the status, such as a decreasing or an increasing thickness, of a layer in response to a single light beam produced from a chamber in which the layer is processed, as by etching or sputtering, by the use of plasma, a monitoring device splits, according to spectral regions, the beam into two components of intensities variable with time and calculates a difference between the intensities, a power of the difference, and a ratio between the intensities. The status is monitored by selecting the difference, power, and ratio. The spectral regions may be 3962 and 3050 A for an aluminum layer being etched and 3248 and 8115 A for a copper layer sputter-formed in argon. Preferably, the difference and the power are monitored a predetermined interval of time after start of etch. The ratio is used in combination with a plasma sputtering device.
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