Plasma removal of Parylene C
Parylene C, an emerging material in microelectromechanical systems, is of particular interest in biomedical and lab-on-a-chip applications where stable, chemically inert surfaces are desired. Practical implementation of Parylene C as a structural material requires the development of micropatterning techniques for its selective removal. Dry etching methods are currently the most suitable for batch processing of Parylene structures. A performance comparison of three different modes of Parylene C plasma etching was conducted using oxygen as the primary reactive species. Plasma, reactive ion and deep reactive ion etching techniques were explored. In addition, a new switched chemistry process with alternating cycles of fluoropolymer deposition and oxygen plasma etching was examined to produce structures with vertical sidewalls. Vertical etch rates, lateral etch rates, anisotropy and sidewall angles were characterized for each of the methods. This detailed characterization was enabled by the application of replica casting to obtain cross sections of etched structures in a non-destructive manner. Application of the developed etch recipes to the fabrication of complex Parylene C microstructures is also discussed.
Additional Information© IOP Publishing Limited 2008. Received 20 November 2007, in final form 13 January 2008. Published 22 February 2008. Print publication: Issue 4 (April 2008). This work was supported in part by the Engineering Research Centers Program of the NSF under Award Number EEC-9402726 and EEC-0310723. We would like to thank Seiji Aoyagi for performing pilot studies, Trevor Roper and Damien Rodger for assistance in fabrication, John Curulli for SEM sample preparation, Arwen Wyatt-Mair for assistance with data analysis, and Tuan Hoang for help with proofreading. We would also like to thank Merrill Roragen, Min-Hsiung Shih and Hongyu Yu for assistance with SEM imaging.
Published - MENjmm08.pdf