Measuring Inorganic Impurities in Semiconductor Manufacturing

Importance of Topic

The semiconductor industry demands ultra-high purity chemicals and materials to control metallic and nanoparticle contamination, which can compromise device performance and yield. ICP-MS, and especially triple quadrupole ICP-QQQ with MS/MS operation, offers the sensitivity, interference removal, and matrix tolerance needed to detect trace and ultratrace impurities in process gases, solvents, wafers, and substrates.

Objectives and Study Overview

This compendium reviews the development and application of single quadrupole and triple quadrupole ICP-MS techniques across semiconductor manufacturing. Key topics include automated surface metal extraction (VPD-ICP-MS), analysis of organic solvents and corrosive acids, online monitoring of process chemicals, nanoparticle characterization, and gas chromatographic separation of metal carbonyls and hydride gases with ICP-QQQ detection.

Methodology and Instrumentation

• Vapor Phase Decomposition (VPD) coupled with ICP-MS or ICP-QQQ for silicon wafer surface analysis, with automated sampling modules.
• High-purity solvent analysis using cooled spray chambers, oxygen addition to prevent carbon deposition, NH3 and H2 collision/reaction cell modes, and optional inert sample introduction kits.
• Nanoparticle analysis by fast Time Resolved Analysis (TRA) mode on ICP-QQQ, with single particle software for multi-element NP characterization and size distribution.
• Online sample preparation and automated standard addition (ASAS or prepFAST S) integrated with ICP-QQQ for streamlined ultratrace calibration.
• GC-ICP-QQQ methods for hydride gases and metal carbonyls, employing MS/MS mass-shift or on-mass modes with O2, H2, or He cell gases, and Deans switch venting for gas matrices.

Main Results and Discussion

• VPD-ICP-QQQ achieved ppt-level detection of >20 trace elements on 300 mm wafers, outperforming single quad methods.
• Hot-plasma ICP-QQQ with m-lens delivered sub-ppt BECs for 26 SEMI elements, including P, S, Si, Cl, in ultrapure water and hydrogen peroxide.
• Automated MSA with prepFAST S and 8900 ICP-QQQ provided 20 ppt detection limits and spike recoveries of 90–110% in H2O2 and IPA.
• spICP-QQQ characterized 15–30 nm Fe, Ag, Al, Au, and SiO2 NPs in solvents, with nebulization efficiencies ~30%, stable size and concentration over 12 h, and linear quantification from 0.1 to 2 ppt NP levels.
• GC-ICP-QQQ methods achieved sub-ppb DLs for hydride gases (PH3, H2S, COS, SiH4, GeH4, AsH3) and metal carbonyls (Ni, Fe, Co, Cr, Mo) using single injections and multi-tune MS/MS acquisition.

Benefits and Practical Applications

• ICP-QQQ with MS/MS ensures reliable, interference-free quantification at single-digit ppt or lower.
• Automated sample preparation systems (prepFAST S, ASAS) minimize manual handling, reduce contamination risk, and increase laboratory productivity.
• spICP-QQQ enables simultaneous multi-element nanoparticle analysis in complex matrices.
• GC-ICP-QQQ extends ICP-MS utility to gas analysis, providing rapid, multi-component monitoring of hydride gas and carbonyl impurities.

Future Trends and Opportunities

• Continued miniaturization of IC devices will drive demand for even lower detection limits and wider scope of analytes, including non-metals and organics.
• Integration of in-line monitoring and process control with ICP-QQQ will enable real-time contamination management in fab environments.
• Further automation and validation of nanoparticle and gas analysis workflows will expand the application of ICP-MS in semiconductor R&D and manufacturing.
• Development of standardized protocols for emerging process chemistries and advanced materials will require customized ICP-QQQ methods.

Conclusion

Agilent ICP-QQQ systems, combined with advanced sample preparation and GC interfaces, deliver the performance and versatility required for the stringent analytical demands of semiconductor manufacturing. From wafer surface extraction to solvent and gas analysis, triple quadrupole ICP-MS with MS/MS provides robust interference control, ultralow detection limits, and multi-element capability, supporting current and future purity specifications across the semiconductor supply chain.

Reference

1. SEMI C41-0705, Specifications and Guidelines for 2-Propanol, Semiconductor Equipment and Materials International, 2005.
2. Applications of ICP-MS: Measuring Inorganic Impurities in Semiconductor Manufacturing, Agilent Technologies, publication 5991-9495EN.
3. Technical Overview of Agilent 8900 Triple Quadrupole ICP-MS, Agilent publication 5991-6942EN.
4. Kazuo Yamanaka et al., Determination of Ultratrace Elements in High Purity Hydrogen Peroxide with Agilent 8900 ICP-QQQ, Agilent publication 5991-7701EN.
5. Michiko Yamanaka and Steve Wilbur, Single Particle Analysis of Nanoparticles using Agilent 8900 ICP-QQQ, Agilent publication 5994-0310EN.
6. W. M. Geiger and E. Soffey, Sub-ppb Detection Limits for Hydride Gas Contaminants using GC-ICP-QQQ, Agilent publication 5991-5849EN.