Patent Number: 6,309,555

Title: Method for determining thickness of material layer and chemical mechanicalpolishing endpoint

Abstract: A method for real-time detecting the thickness of a material layer. Areflected light is measured of an incident light emitted toward thematerial layer. By integrating the intensity of the reflected light alongthe time axis, followed by dividing by the product of the derivative ofthe intensity of the reflected light and the polishing time, an I-Dttransformation curve can be obtained. Since the I-Dt transformation curvehas characteristics associated with a cosecant function, which has salientpeaks on the curve, the thickness of the material layer can be real-timedetermined. Furthermore, due to the facts that the transformed curve hassalient peaks, the function itself reveals the sign of the slope, and thetransformed curve are relatively flat between peaks, correct and stablerules can therefore be provided to determine the analytical endpoint.

Inventors: Chen; Hsueh-Chung (Taipei Hsien, TW)


International Classification:

Expiration Date: 10/32013