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Chemical-mechanical polishing of recessed microelectromechanical devices

United States Patent

July 6, 1999
View the Complete Patent at the US Patent & Trademark Office
Sandia National Laboratories - Visit the Intellectual Property Management and Licensing Website
A method is disclosed for micromachining recessed layers (e.g. sacrificial layers) of a microelectromechanical system (MEMS) device formed in a cavity etched into a semiconductor substrate. The method uses chemical-mechanical polishing (CMP) with a resilient polishing pad to locally planarize one or more of the recessed layers within the substrate cavity. Such local planarization using the method of the present invention is advantageous for improving the patterning of subsequently deposited layers, for eliminating mechanical interferences between functional elements (e.g. linkages) of the MEMS device, and for eliminating the formation of stringers. After the local planarization of one or more of the recessed layers, another CMP step can be provided for globally planarizing the semiconductor substrate to form a recessed MEMS device which can be integrated with electronic circuitry (e.g. CMOS, BiCMOS or bipolar circuitry) formed on the surface of the substrate.
Barron; Carole C. (Albuquerque, NM), Hetherington; Dale L. (Albuquerque, NM), Montague; Stephen (Albuquerque, NM)
Sandia Corporation (Albuquerque, NM)
08/ 915,071
August 20, 1997
GOVERNMENT RIGHTS This invention was made with Government support under Contract No. DE-AC04-94AL85000 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.