Patent ID: 6801322
Filing Date: 2004-10-05
Classification: B24B

Abstract:
A method of in-situ measuring a required feature of an inspected layer within a structure during a polishing process that is carried out by a polish apparatus, the method comprising:providing a structure having a substrate and an inspected layer, wherein the substrate has a front side and a backside and the inspected layer is over the front side; projecting a pump laser pulse on a pump area of the backside of the substrate; absorbing energy of the pump layer pulse on the backside of the substrate; generating a sound wave that propagates into the structure; projecting a probe laser beam on a probe area of the backside of the substrate, the probe laser beam being reflected on the probe area forming a reflected probe laser beam; measuring properties of the reflected probe laser beam as a function of time; and determining the required feature of the inspected layer from the measured properties of the reflected probe laser beam as a function of time.