Method and apparatus for measuring abrasion amount and pad friction force of polishing pad using thickness change of slurry film

Abstract

A method and apparatus for measuring an abrasion amount and a friction force of a polishing pad using a thickness change of a slurry film in a chemical mechanical polishing operation are provided. In a preferred method, for example, a first displacement of a semiconductor wafer with respect to a polishing pad is measured during an initial stage and a first reference range of the thickness change of the slurry film is preferably set to determine a replacement time corresponding to the abrasion amount of the polishing pad. A conditioning condition of the polishing pad conditioning can also be set, and a second displacement of the semiconductor wafer with respect to the polishing pad can be measured when the surface of the semiconductor wafer is polished by the polishing pad. The first displacement is then preferably compared with the second displacement to calculate the thickness change of the slurry film formed between the polishing pad and the semiconductor wafer. When the thickness change of the slurry film is out of the first reference range, the polishing pad is preferably replaced. When the surface state of the polishing pad corresponding to the thickness change of the slurry film fails the conditioning condition, a conditioning operation to condition the surface of the polishing pad is preferably performed.