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The Effect of Inhibitors on the Electrochemical Deposition of Copper Through-silicon Via and its CMP Process Optimization

Through silicon via (TSV) technology is extensively used in 3D IC integrations. The special structure of the TSV is realized by CMP (Chemically Mechanical Polishing) process with a high Cu removal rate and, low dishing, yielding fine topography without defects. In this study, we investigated the ele...

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Bibliographic Details
Published in:Journal of semiconductor technology and science 2017, 17(3), 75, pp.319-325
Main Authors: Paul-Chang Lin, Jin-Hai Xu, Hong-Liang Lu, David Wei Zhang, Pei Li
Format: Article
Language:English
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Summary:Through silicon via (TSV) technology is extensively used in 3D IC integrations. The special structure of the TSV is realized by CMP (Chemically Mechanical Polishing) process with a high Cu removal rate and, low dishing, yielding fine topography without defects. In this study, we investigated the electrochemical behavior of copper slurries with various inhibitors in the Cu CMP process for advanced TSV applications. One of the slurries was carried out for the most promising process with a high removal rate (~18000 Å/Min @ 3 psi) and low dishing (~800 Å), providing good microstructure. The effects of pH value and H2O2 concentration on the slurry corrosion potential and Cu static etching rate (SER) were also examined. The slurry formula with a pH of 6 and 2% H2O2, hadthe lowest SER (~75 Å/Min) and was the best for TSV CMP. A novel Cu TSV CMP process was developed with two CMPs and an additional annealing step after some of the bulk Cu had been removed, effectively improving the condition of the TSV Cu surface and preventing the formation of crack defects by variations in wafer stress during TSV process integration. KCI Citation Count: 0
ISSN:1598-1657
2233-4866
DOI:10.5573/JSTS.2017.17.3.319