Method for forming an apparatus for in-situ endpoint detection and monitoring for chemical mechanical polishing operations

摘要

The disclosure relates to an apparatus for chemical mechanical polishing (CMP) of a wafer, comprising: a rotatable polishing patent (16) with an overlying polishing pad (18) wetted with an abrasive slurry, the platen being rotatably mounted to a chassis; a rotatable polishing head (12) for holding the wafer (14) against the polishing pad, the wafer comprising a semiconductor substrate underlying an oxide layer; and an endpoint detector. The detector comprises a laser interferometer (32) capable of generating a laser beam directed towards the wafer and detecting light reflected from the wafer, and a window (38) disposed adjacent a hole (30) formed through the platen, the window providing a pathway for the laser beam to impinge on the wafer at least during part of a period of time when the wafer overlies the window.