| 摘要 |
An endpoint detector and performance monitoring system for quickly and accurately measuring the change in thickness of a wafer and other planarizing parameters in chemical-mechanical polishing processes. In one embodiment, an endpoint detector has a reference platform, a measuring face, and a distance measuring device. The reference platform is positioned proximate to the wafer carrier, and the reference platform and measuring device are positioned apart from one another by a known, constant distance. The measuring face is fixedly positioned with respect to the wafer carrier at a location that allows the measuring device to engage the measuring face when the wafer is positioned on the reference platform. Each time the measuring device engages the measuring surface, it measures the displacement of the measuring face with respect to the measuring device. The displacement of the measuring face is proportional to the change in thickness of the wafer between measurements. In another embodiment, a planarizing machine has a flat plate, a planarizing medium fastened to the plate, a carrier assembly to manipulate a substrate holder over the planarizing medium, and a non-contact distance measuring device. The non-contact distance measuring device measures the actual elevation of the substrate holder as the substrate holder engages a substrate with the planarizing medium and relative motion occurs between the substrate holder and the planarizing medium. The performance monitoring system uses the actual pad elevation to determine the endpoint, the polishing rate and other CMP operating parameters.
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