Accurate and Reproducible Analysis of TMAH and UPW Quantitation in the Low ppq Level​

Roundtable handout from February Community Event

This presentation was given as part of the Ultrapure Micro 2021 annual conference. It was given as part of the ultrapure water strand.

The ability to conduct current through a liquid is measured by conductivity and can be related to the concentrations of ions in the solution. In this work, a patented analytical technique is used to quantify the contaminant level of specific chemicals in an on-line ultrapure water (UPW) system. The method uses a resistivity system with additional mathematical techniques to exploit the physical relationship between temperature and resistivity. This method utilises the slope between resistivity/temperature curves and not the absolute resistivity. The theoretical conductance of chemicals is compared with experimentally-measured values from 1 parts-per-trillion (ppt) to 10 parts-per-billion (ppb). This work helps establish the characteristics of compounds that can be measured with this technique and determines the limits of detection, and therefore has a potential commercial application. High conductance compounds like sodium chloride and potassium hydrogen phthalate are measurable at the 100 ppt level while low conductance compounds like boric acid cannot be discerned from the background. As the method matures into a product the limits of detection should be lowered. This article was originally published in the Ultrapure Micro Journal in March 2019.

This presentation was given at the Ultrapure Micro 2020 annual conference. It was presented in the Ultrapure Water Production track, as part of the UPW Process Optimization session.

This presentation was given at the Ultrapure Micro 2020 annual conference. It was presented in the Ultrapure Water Production track, as part of the Wafer Contamination Control - Particles Monitoring session.

This presentation was given at the Ultrapure Micro 2018 annual conference. It was presented in the Ultra High Performance Chemicals and High Purity Gases track, as part of the High Purity Chemicals in Semiconductor Manufacturing session.

This presentation was given at the Ultrapure Micro 2018 annual conference. It was presented in the Ultrapure Water Production track, as part of the Particle Analysis and Control in UPW session.

This presentation was given at the Ultrapure Micro 2017 annual conference. It was presented in the Ultrapure Water Production track, as part of the UPW System Optimization session.

This presentation was given at the Ultrapure Micro 2017 annual conference. It was presented in the Ultrapure Water Production track, as part of the UPW Particle Measurement and Control session.

This presentation was given at the Ultrapure Micro 2015 annual conference. It was presented in the Ultrapure Water Production track, as part of the Metrology session.