Chemical mechanical planarization (CMP) of a semiconductor wafer using acoustical waves for in-situ end point detection
Patent 5240552 Issued on August 31, 1993. Estimated Expiration Date: 
December 11, 2011. 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.
December 11, 2011. 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 3841031 Polishing apparatus Counterbalanced polishing apparatus Method of endpoint detection during chemical/mechanical planarization of semiconductor wafers Patent #: 5036015 InventorsApplicationNo. 806096 filed on 12/11/1991US Classes:438/5, INCLUDING CONTROL RESPONSIVE TO SENSED CONDITION257/E21.244, Involving dielectric removal step (EPO)438/14, WITH MEASURING OR TESTING438/692, Simultaneous (e.g., chemical-mechanical polishing, etc.)438/959MECHANICAL POLISHING OF WAFERExaminersPrimary: Hearn, Brian E.Assistant: Holtzman, Laura M. Attorney, Agent or FirmForeign Patent References
International ClassH01L 021/00AbstractA method and apparatus for chemically mechanically planarizing (CMP) a semiconductor wafer includes directing acoustic waves at the wafer and receiving reflected acoustic waves from the wafer during the (CMP) process. By analyzing the acoustic waves and reflected acoustic waves a thickness of the wafer can be determined and an endpoint and thickness of films formed on the wafer can be monitored in real time during the (CMP) process. The process parameters of the (CMP) process can then be adjusted as required to improve the uniformity of the process.Other References
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