Technical Overview and Performance Capability of the Agilent 7900s ICP-MS for Semiconductor Applications

Significance of the Topic

In semiconductor fabrication, even femtogram-level metal impurities in high-purity reagents can compromise device performance and yield. Advanced analytical tools that deliver ultra-low detection limits, robust interference control, and stable operation in cleanroom environments are therefore essential.

Objectives and Overview of the Article

This paper presents the technical capabilities and performance data of the Agilent 7900s ICP-MS system tailored for semiconductor process chemicals. It surveys the instrument’s design goals, interference-removal strategies, sensitivity in both aqueous and organic matrices, and long-term measurement stability.

Methodology and Instrumentation

The study employed cool and hot plasma modes, combined with a fourth-generation octopole collision/reaction cell (ORS4). Helium kinetic energy discrimination (KED) and hydrogen reaction modes were used to suppress polyatomic overlaps, while ammonia was applied selectively for difficult ClO+ interferences in concentrated HCl. Automated cell-gas switching within each sample visit optimized throughput and minimized sample consumption.

Used Instrumentation

• Agilent 7900s ICP-MS with frequency-matching solid-state RF generator
• ORS4 collision/reaction cell with up to three gas lines (He, H2, NH3)
• Off-axis Omega ion lens and Orthogonal Detector System for high ion transmission
• PFA nebulizer, platinum interface, and “s-type” ion lens for semiconductor purity
• Optional organics torch (1.5 mm ID) for direct analysis of volatile solvents
• ICP-MS MassHunter software with autotune, preset methods, and IntelliQuant profiling

Main Results and Discussion

• Aqueous DLs and BECs: Most elements achieved detection limits near 0.1 ng/L (ppt) in 1% HNO₃; cool plasma further reduced background for Na, K, Ca, and Fe.
• Interference removal: ORS4 in enhanced He mode improved P quantification by 10–50×; H₂ reaction mode enabled direct ²⁸Si measurement by eliminating N₂⁺ overlaps.
• Special cases: NH₃ mode provided a 2.3 ppt detection limit for ⁵¹V in 20% HCl by removing ClO⁺ interferences.
• Organic matrices: Undiluted IPA analyses delivered single-ppt BECs and DLs; signal drift remained below 5% RSD over four hours in both hot and cool modes.
• Stability and throughput: Automatic switching between plasma modes and cell gases yielded <5% drift over a nine-hour run for 100 ppt spikes in 1% HNO₃.

Benefits and Practical Applications

The Agilent 7900s offers semiconductor labs:

• Exceptional sensitivity and sub-ppt detection across diverse chemical matrices
• Rapid mode switching for high sample throughput with minimal contamination risk
• Compact bench-top footprint and low utility demands suitable for cleanrooms
• User-friendly software with autotuning and IntelliQuant to support novice analysts

Future Trends and Opportunities

Advances likely include integration with triple-quadrupole ICP-MS for targeted interference control, AI-driven method development, nanoparticle characterization in process fluids, and further miniaturization of high-performance ICP-MS systems for inline process monitoring.

Conclusion

The Agilent 7900s ICP-MS combines robust cool-plasma capability, a high-energy ORS4 cell, and stable operation in organic solvents to meet the stringent requirements of semiconductor trace analysis. Its performance data demonstrate ultra-low detection limits, reliable interference removal, and long-term stability, positioning it as a leading solution for high-purity chemical monitoring.

References

• Agilent Technologies. Technical Overview and Performance Capability of the Agilent 7900s ICP-MS for Semiconductor Applications. White Paper, April 2020.