Ensuring the quality of advanced process chemicals is crucial in semiconductor manufacturing. However, traditional offline particle analysis methods sometimes classify these chemicals as unqualified, highlighting the need for more effective evaluation techniques. Single-particle inductively coupled plasma mass spectrometry (SP-ICPMS) has emerged as a promising solution for detecting and characterizing particles on wafer surfaces.

In this study, nanoparticles on wafer surfaces were analyzed. The wafers were cleaned using a mixture of NH4OH (29%), H2O2 (31%), and ultra-pure water (UPW), also known as AMP clean solution. After cleaning, the solution was analyzed using SP-ICPMS to determine particle presence and concentration. The method was validated by adding 30 nm Fe particles to wafer surfaces, drying them, and then cleaning with AMP solution before analysis.

One challenge faced during this process was background interference from the silicon-based wafers, particularly during the extraction of SiO₂ particles. To mitigate this, metal-coated wafers were used to differentiate SiO₂ particles from the wafer background. Various cleaning solutions, such as AMP, IPA, and TMAH, were also tested to optimize particle removal and minimize background interference.

Initial results revealed that using AMP and IPA led to significant carbon background interference, complicating the analysis of carbon-based particles. This issue was likely caused by the wafer's main components and environmental factors. The QC lab developed specific methods for analyzing particles directly on the wafer surface, using standard polymer particles to validate the approach.

In conclusion, the SP-ICPMS method developed for nanoparticle analysis shows promise in improving the assessment of advanced process chemicals. Further refinement is needed, especially in addressing carbon background interference, to ensure accurate particle detection and characterization.