Patent ID: 6623993
Filing Date: 2003-09-23
Classification: B24B,H01L

Abstract:
A method of determining the time for polishing the surface of an integrated circuit wafer to be polished on a polishing machine so as to remove from a layer of a material to be polished a predetermined average thickness and confer a particular final topography, the wafer to be polished being gripped by the polishing machine at a particular pressure between a rotary head and a polishing cloth carried by a turntable and covered with an abrasive material, said method comprising the steps of:fabricating a sample wafer by depositing a layer of the material to be polished such that the layer forms at least one high plateau and at least one low plateau that are joined by a sudden transition; topographically scanning at least one initial profile of the layer that includes the transition on the surface of the sample wafer; polishing the surface of the sample wafer on the polishing machine at a particular polishing pressure for a particular polishing time; topographically scanning the final profile of the polished layer in an area corresponding to the initial profile; converting the initial topographical scan and the final topographical scan of the sample wafer into Fourier series; topographically scanning the surface of the wafer to be polished; converting the topographical scan of the wafer to be polished into a Fourier series; and calculating the time for polishing the wafer to be polished from the Fourier series and the average thickness to be removed, wherein the sample wafer is not identical to the wafer to be polished.