Lamp failure detector

摘要

Apparatus and methods for detecting lamp failure in a rapid thermal processing (RTP) tool are provided. Lamp failure detection systems are provided that can accommodate DC and/or AC voltages. The systems sample voltage signals along a circuit path formed by at least two serially connected lamps, calculate a voltage drop across the first lamp of the at least two serially connected lamps based on the sampled voltage signals, and determine whether a lamp failure has occurred based on a relationship between the voltage drop across the first lamp and a total voltage applied to the circuit path.

主权项

1. 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 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; anda 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 the circuit path in parallel with the first lamp and a filter rectifier coupled to the first resistor, wherein the filter rectifier comprises a bridge rectifier having ends coupled in parallel with the first resistor, and wherein the filter rectifier further comprises a measurement capacitor coupled in parallel with taps of the bridge rectifier.