Title: Polishing CVD diamond wafer by compound methods

Authors: Zewei Yuan; Zhuji Jin; Quan Wen; Kun Wang

Addresses: No. 2, Linggong Road, Ganjingzi District, Dalian City 116024, LiaoNing Province, China. ' No. 2, Linggong Road, Ganjingzi District, Dalian City 116024, LiaoNing Province, China. ' No. 2, Linggong Road, Ganjingzi District, Dalian City 116024, LiaoNing Province, China. ' No. 2, Linggong Road, Ganjingzi District, Dalian City 116024, LiaoNing Province, China

Abstract: Chemical vapour deposition (CVD) diamond wafer, as the material for optical transmission windows and new-generation computer chips, is required to be fine polished. However, no individual method can polish CVD diamond wafer with high efficiency and fine polishing quality. This paper attempts to polish CVD diamond wafer by compound method to solve this problem. With the method, CVD diamond wafer is first processed by electro-discharge machining (EDM) to remove course asperities, and subsequently polished by chemical mechanical polishing (CMP) to achieve fine surface. According to the experimental results, the roughness of CVD diamond wafer processed by EDM was reduced to Ra 0.781 µm from Ra 13.3 µm, and further reduced to Ra 1.284 nm polished by CMP. The material removal during EDM process can be a chemo-mechanical process, including gasification, melting, sputtering, oxidation and graphitisation. The graphitisation of the surface of CVD diamond wafer ensures EDM to be continued. While in CMP process, diamond is removed under the mechanical and tribochemical interaction.

Keywords: CVD diamond wafers; electroless nickel phosphorous; electro-discharge machining; electrical discharge machining; EDM; chemical mechanical polishing; CMP; chemical vapour deposition; wafer polishing.

DOI: 10.1504/IJMMM.2012.044924

International Journal of Machining and Machinability of Materials, 2012 Vol.11 No.1, pp.69 - 83

Received: 15 Oct 2010
Accepted: 06 Dec 2010

Published online: 23 Aug 2014 *

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