Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10419549 | Precision Engineering | 2005 | 6 Pages |
Abstract
The surface waviness with concentric circular pattern is generated on highly-boron-doped Si wafer by chemical-mechanical polishing (CMP) with amine system polishing slurry. To investigate the generation mechanism of the waviness, the mechanical and chemical characteristics were clarified using the silicon crystal samples with various boron concentration level ranging from 2.9Â ÃÂ 1017Â cmâ3 to 1.3Â ÃÂ 1020Â cmâ3. The conventional silicon substrate used as epitaxial wafer has boron concentration of about 2.5Â ÃÂ 1018Â cmâ3, a region at which the radical change of etching rate is induced with amine system chemical reagent. The mechanical micro-hardness of highly-boron-doped Si is 30% higher than that of lightly-doped Si. It is found that SiB bond in crystal lattice is firmed up and stabilized for mechanical stress and chemical reaction. To cancel the difference in CMP rate based on boron concentration deviation, increasing the mechanical action in CMP was proposed and performed. The precision CMP was performed using the harder polishing pad and a smooth surface without waviness was obtained.
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Authors
J. Watanabe, G. Yu, O. Eryu, I. Koshiyama, K. Izumi, K. Nakashima, M. Umeno, T. Jimbo, K. Kodama,