Quantification issues of trace metals analysis on silicon oxide and nitride films by using VPD‐ICP‐MS and VPD‐GF‐AAS |
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Authors: | Ming‐Peng Yeh Casey Hsien Cheng‐Sung Huang Ter‐Chuan Lin |
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Institution: | 1. Micro‐contamination control, Promos, No. 19, Ke Ya road, Daya Township, Taichung County 428, Taiwan, Republic of China;2. Micro‐contamination control, Promos, Taichung, Taiwan, Republic of China;3. CTSIP manufacturing, Promos, Taichung, Taiwan, Republic of China |
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Abstract: | Vapor phase decomposition (VPD) is a pretreatment technique for collecting trace metal contaminants on the surface of a Si wafer. Such trace metals can be identified and quantified by inductively coupled plasma mass spectrometry (ICP‐MS) or graphite furnace atomic absorption spectroscopy (GF‐AAS). However, the analytical results can be influenced by the Si‐matrix in the VPD samples. This article discusses the approaches to eliminate the interference caused by Si‐matrix. When the thickness of oxide film on wafer surface is less than 100 Å, the quantification results of ICP‐MS analysis will not be affected by Si‐matrix in the VPD samples. Except this, the Si‐matrix must be removed before analysis. An improved heating pretreatment approach has been adopted successfully to eliminate the Si‐matrix. For GF‐AAS analysis, the Si‐matrix will influence the sodium and aluminum analyses. Adding HNO3 to the graphite furnace tubing after sample injection could also eliminate the interference caused by the Si‐matrix. The method detection limits (MDLs) of VPD‐GF‐AAS and VPD‐ICP‐MS range from 0.04 to 0.55 × 1010 atoms cm?2 and 0.05 to 1.73 × 109 atoms cm?2, respectively. Copyright © 2008 John Wiley & Sons, Ltd. |
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Keywords: | silicon wafer VPD‐ICP‐MS VPD‐GF‐AAS |
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