Patent ID: 8304264

Claim:
A chamber-status monitoring apparatus for use in semiconductor fabrication, the apparatus comprising: a plurality of chambers configured to perform etching processes on semiconductor wafers; a time-division multiplexer connected to each of the chambers via at least one respective optical fiber probe, the time-division multiplexer being configured to receive, via the at least one respective optical fiber probe, an optical signal from each chamber in accordance with corresponding plasma emission in the chamber, to divide each optical signal into first time slots having a predetermined duration, and to multiplex the first time slots of all the optical signals to generate an optical time-division multiplexed (OTDM) signal; a multi-input optical emission spectroscope connected to the time-division multiplexer via an optical fiber probe, the multi-input optical emission spectroscope being configured to receive the OTDM signal from the time-division multiplexer and to disperse the OTDM signal according to wavelengths to measure spectrum information; and a controller configured to divide the spectrum information of the dispersed OTDM signal into second time slots with a predetermined time interval therebetween, to classify the second time slots according to the chambers to obtain spectrum information of the optical signals of the individual chambers, and to control endpoint detection in each of the chambers in accordance with the spectrum information of the optical signal of the corresponding chamber.