Method of endpoint detection during chemical/mechanical planarization of semiconductor wafers
September 24, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3699722 3841031 Process for chemical-mechanical polishing of III-V semiconductor materials Polishing apparatus End point detection method for physical etching process Method for machining workpieces of brittle hard material into wafers In situ conductivity monitoring technique for chemical/mechanical planarization endpoint detection Counterbalanced polishing apparatus Integrated circuit planarization by mechanical polishing Wafer flood polishing InventorsApplicationNo. 586996 filed on 09/24/1990US Classes:438/14, WITH MEASURING OR TESTING216/84, With measuring, testing, or inspecting257/E21.244, Involving dielectric removal step (EPO)438/693, Utilizing particulate abradant451/1, PRECISION DEVICE OR PROCESS - OR WITH CONDITION RESPONSIVE CONTROL451/41Glass or stone abradingExaminersPrimary: Hearn, Brian E.Assistant: Trinh, Michael Attorney, Agent or FirmInternational ClassH01L 021/66AbstractA method and apparatus for detecting a planar endpoint on a semiconductor wafer during chemical/mechanical planarization of the wafer. The planar endpoint is detected by sensing a change in friction between the wafer and a polishing surface. This change of friction may be produced when, for instance, an oxide coating of the wafer is removed and a harder material is contracted by the polishing surface. In a preferred form of the invention, the change in friction is detected by rotating the wafer and polishing surface with electric motors and measuring current changes on one or both of the motors. This current change can then be used to produce a signal to operate control means for adjusting or stopping the process. | |
