DEVICE OF MEASURING WAFER METAL LAYER THICKNESS IN CHEMICAL MECHANICAL POLISHING APPARATUS AND METHOD THEREOF

摘要

The present invention relates to a wafer layer thickness monitoring device in a chemical mechanical polishing system and a method thereof. The wafer layer thickness monitoring device in the chemical mechanical polishing system comprises multiple first light emitting units arranged in the circumferential direction of a retainer ring of a carrier head which pressurizes a wafer on a polishing pad; and a first light receiving unit for receiving light from the first light emitting unit by being disposed at the lower side of the polishing pad. The wafer layer thickness monitoring device in the chemical mechanical polishing system reliably detects that a transparent window of the polishing pad rotatably moves and reaches the lower side of the wafer by detecting that the transparent window is disposed at the lower side of the wafer as the light emitted from the first light emitting unit reaches the first light receiving unit through the transparent window.