Analytical Sciences

Collection Efficiency of Metallic Contaminants on Si Wafer by Vapor-Phase Decomposition-Droplet Collection

Hye-Young CHUNG,* Young-Hun KIM,* Hyo-Yong CHO,* Bo-Young LEE,* Hak-Do YOO,* and Sang-Hak LEE**

*R&D Center, LG Siltron Inc., 283, Imsoo-dong, Kumi, Kyungbuk, 730-350, Korea
**Department of Chemistry, Kyungpook National University, 1370 Sankyuk-dong, Puk-gu, Taegu 702-701, Korea

The collection efficiency of metallic contaminants on four different types of silicon wafers was investigated. P, p⁺, n and n⁺-type polished silicon wafers were used for the substrate, and 14 metallic elements (Na, Mg, Al, K, Ca, Cr, Fe, Mn, Co, Ni, Cu, Zn, Mo and Ti) were contaminated on silicon wafer surface. Vapor-phase decomposition-droplet collection (VPD-DC) was employed as the sample preparation procedure. For the collecting solution, HNO₃, HF and a mixture of HF and H₂O₂ were used, respectively. A liquid droplet collecting metallic contaminants during VPD-DC was analyzed by inductively coupled plasma-mass spectrometry (ICP-MS). As a result, it was found that HNO₃ and HF were not suitable for collecting Cu. Copper was not collected completely in HNO₃ and HF. A mixture of HF and H₂O₂ is the most effective to collect all of the tested metallic elements, regardless of the dopant concentration and type of substrate.

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