Endpoint detection in the fabrication of electronic devices

摘要

A chamber 28 comprises a radiation source 58 capable of emitting radiation having a wavelength that is substantially absorbed in a predetermined pathlength in a thickness of a layer 22 on a substrate, and a radiation detector 62 adapted to detect the radiation. The radiation is substantially absorbed in a first thickness of the layer 22, and after at least partial processing of the layer 22, is at least partially transmitted through a second thickness of the layer 22 and reflected by one or more underlayers 24 of the substrate 20.