Online Measurement of Total Active Ions of Chemicals at Sub-ppb Levels Using Advanced Resistivity Algorithms

:Organic contaminants, including high molecular weight organics, in semiconductor grade chemicals (IPA, H2O2, H2SO4, NH4OH, UPW, etc.) are identified and quantified at concentrations required by the IRDS. New metrology is needed for online detection of organic contaminants. This includes critical organic compounds which may have boiling points greater than 200 degrees C, considered high molecular weight, and can create particles that are detrimental to the wafer making process. . Elemental Scientific has implemented new technology to address these issues and monitor for all possible organic contaminants (low molecular weight to high molecular weight compounds) in ultra-pure chemicals. This tool monitors chemicals for known (targeted) and unknown (non-targeted) organic contaminants, providing identification and quantification in a routine automated fashion. This process is important to the overall wafer production and the integrity of the final product.

This presentation was given as part of the Ultrapure Micro 2021 annual conference. It was given as part of the ultra high purity chemicals 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 Q&A session took place at the 2020 Ultrapure Micro annual conference. It was a part of the AMC, Liquid Chemicals & Gases Control track, and included speakers from the Contamination Control in Liquid Chemicals session.

This presentation was given at the Ultrapure Micro 2020 annual conference. It was presented in the AMC, Liquid Chemicals & Gases Control track, as part of the Contamination Control in Liquid Chemicals 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 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 Ultra High Performance Chemicals and High Purity Gases track, as part of the High Purity Chemicals in Semiconductor Manufacturing session.