Patent ID: 8878461

Claim:
An apparatus for thermal processing of semiconductor substrates, comprising: a chamber body having an opening; a lamphead assembly coupled to the opening of the chamber body, the lamphead assembly comprising a plurality of lamps arranged in an array; and a lamp failure detector electrically coupled to the lamphead assembly and comprising: a voltage data acquisition module positioned to sample alternating current (AC) voltage signals on a circuit path formed by at least two serially connected lamps of the plurality of lamps; a first capacitor coupled to the circuit path at a first node associated with a first lamp of the at least two serially connected lamps and coupled to the voltage data acquisition module; and a second capacitor coupled to the circuit path at a second node associated with the first lamp of the at least two serially connected lamps and coupled to the voltage data acquisition module; and a controller adapted to receive digital values of the sampled voltage signals from the voltage data acquisition module, and to determine a status of one or more lamps of the at least two serially connected lamps based on a voltage drop across the first lamp of the at least two serially connected lamps, as determined by the sampled voltage signals, wherein the lamp failure detector further comprises a first resistor coupled between the first and second capacitors of each circuit path in parallel with the first lamp and a filter rectifier coupled to the first resistor, the filter rectifiers each comprising: a bridge rectifier having ends coupled in parallel with the first resistor; a measurement capacitor coupled in parallel with taps of the bridge rectifier; and a second resistor coupled in parallel with the measurement capacitor and coupled to the voltage data acquisition module.