Senior Scientist Air Liquide Balazs
Dr. Lisa Mey-Ami is a Senior Scientist and Technical Community Leader within the R&D group at Air Liquide Balazs in Fremont, California. She routinely develops analytical methods to advance trace elemental analysis metrology for water, chemicals, thin films, and advanced materials. Additionally, she has published innovative techniques for detecting elemental nanoparticles in water, chemicals, and etch part surfaces using single nanoparticle inductively coupled plasma mass spectrometry (sNP-ICP-MS). Lisa is an active member of the SEMI and IRDS Water and CCC task forces.
Abstract
Analytical Advances in Sub-10 nm Nanoparticle Characterization for Next-Generation Semiconductor Manufacturing
Nanoparticles (NPs), defined as particles in the 1–100 nm range, are a primary cause of microchip failure in modern semiconductor fabrication. As advanced semiconductor manufacturing nodes reach feature sizes below 5 nm, the threshold for “killer defects” has similarly reduced, necessitating metrology capable of detecting nanoparticles at the single-digit nanometer scale.
Traditional particle measurement techniques, such as Laser Particle Counters (LPC), are best for particles above 100nm, as accurate particle counting can be affected by microbubbles. Moreover, LPC lacks the ability to provide elemental composition of NPs. Single nanoparticle-inductively coupled plasma-mass spectrometry (sNP-ICP-MS) employs time-resolved data acquisition with dwell times as short as 0.1 ms. This allows for the resolution of individual nanoparticle events, enabling the simultaneous determination of elemental particle concentration, median size, and size distribution. In addition, sNP-ICP-MS can achieve background equivalent diameters (BED) in the single-digit nanometer range for critical contaminants.
This study evaluates sNP-ICP-MS methodologies applied to ultrapure water (UPW), encompassing the analysis of customer samples, the assessment of individual stages within UPW production systems, and filter performance testing in semiconductor fabs. Furthermore, the technique is employed to characterize NPs in various processing chemicals, including acids, bases, organics, and ALD precursors. Preliminary investigations were also conducted to detect nanoparticles in inert gases.
Lastly, a novel method has been developed for assessing NPs in extracts from plasma etching chamber components. Recently, an investigation compared particle removal techniques from chamber part surfaces, revealing that megasonic energy extraction provides significantly higher nanoparticle recovery efficiency—up to 10X for certain elements—compared to traditional mechanical shaking. The use of chemical extractants, such as dilute SC-1 (pH 10), combined with megasonic energy, was also found to enhance extraction yields for diverse elemental NPs (e.g., Mg, Ti, Cr, Cu, Ni) across quartz and ceramic substrates.
Ultimately, these findings establish sNP-ICP-MS as a vital analytical tool for characterizing nanoparticles across a diverse range of matrices, from ultrapure water and process chemicals to inert gases and component cleaning extracts. By providing unprecedented sensitivity and elemental specificity, this technology plays a critical role in achieving the stringent cleanliness standards essential for enabling the next generation of semiconductor manufacturing.