Patent ID: 7361601
Filing Date: 2008-04-22
Classification: B24B,H01L

Abstract:
1. A method for improving accuracy of determining a polish endpoint of a chemical mechanical polish (CMP) process, comprising: (a) providing a first test wafer, a to-be-polished layer and a material layer thereunder being formed over the first test wafer; (b) providing a first test beam with a first wavelength to irradiate the first test wafer; (c) performing a CMP process to the first test wafer to remove the to-be-polished layer until exposing the material layer while continuously detecting a reflection of the first test beam during the CMP process; and (d) determining a reflection tendency of the first test beam when the to-be-polished layer is to be completely removed and when the CMP process reaches an interface between the to-be-polished layer and the material layer, if the reflection tendency of the first test beam is decreased, detecting polish endpoints of the other wafers by the first test beam with the first test wavelength and if the reflection tendency of the first test beam is increased, steps (a)-(d) being repeated, second test wafer and second test beam with second wavelength being provided until the reflection tendency is decreased, wherein the first wavelength and the second wavelength are different, and the CMP process to the first test wafer and the CMP process to the second test wafer are preformed under a same condition.