Calibration method for acoustic sensor
AssigneeEbara Corporation
InventorsYuta Suzuki, Taro Takahashi
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Abstract
A method in which an acoustic sensor disposed in a polishing apparatus can be accurately calibrated is disclosed. In this method, polishing sounds of a substrate are acquired using an acoustic sensor; and then at least two distinctive sounds, having distinctive frequencies respectively, are selected from the acquired polishing sounds. Further, the at least two distinctive sounds are output from a sound source coupled to any of a polishing table, the acoustic sensor, and a substrate holder to cause the at least two distinctive sounds to be input to the acoustic sensor. Next, output values of the acoustic sensor are calibrated, such that the output values of the acoustic sensor relative to the at least two distinctive sounds come within an allowable range.
Claims10
A calibration method for an acoustic sensor provided in a polishing apparatus in which a substrate held in a substrate holder is pressed against a polishing pad attached to a polishing table to thereby polish the substrate, comprising:
- acquiring polishing sounds of the substrate using the acoustic sensor;
- selecting at least two distinctive sounds, having distinctive frequencies respectively, from the acquired polishing sounds;
- outputting the at least two distinctive sounds from a sound source coupled to any of the polishing table, the acoustic sensor, and the substrate holder to cause the at least two distinctive sounds to be input to the acoustic sensor;
- and
- calibrating output values of the acoustic sensor, such that the output values of the acoustic sensor relative to the at least two distinctive sounds come within an allowable range, wherein the at least two distinctive sounds are a sound of a frequency having a distinctive peak among the polishing sounds acquired by the acoustic sensor.
Dependencies are inferred from the claim text.