Microanalysis: A novel method to characterize and speciate contaminants in Ultra Pure Water (UPW) and other aqueous chemicals

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.

This article provides an overview of the biggest challenge of UPW technology – particle control. The latest semiconductor technologies require near particle-free water, where the “killer” particle size is far below the size that UPW metrology can effectively detect. Also, current advanced treatment methods cannot guarantee reliable removal of killer-sized particles. The quality of the high-purity materials used downstream of the final filters has not typically been tested for shedding of the “killer” particles. Consequently, the semiconductor industry requires a comprehensive approach for the particle control. A new approach should include mitigating particle occurrence and continuously improving the technologies used in UPW polish and distribution systems. Such an approach should also include extensive use of SEMI standards to improve the quality of the materials used; a new way to engineer solutions related to system-configuration and system design; improved process control; and a careful review of critical operational decisions. Collaboration throughout the industry via IRDS and SEMI Standards is key to enabling such systematic improvement, and overcoming the metrology and other constraints. This article was originally published in the Ultrapure Micro Journal in November 2017.

A newly developed H2O2 monitoring method is capable of continuous measurement without using chemical reagents but catalase-resin instead. This technology also makes it possible to measure H2O2 that is generated in a UV-ox (ultraviolet oxidizer) without interference. This study was conducted to support an ultrapure water (UPW) polishing system, and to compare existing H2O2 monitoring procedures with the new technology. This article was originally published in the Ultrapure Micro Journal in February 2018.

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 Ultrapure Water Production track, and included speakers from the Wafer Contamination Control - Particles Monitoring session.

This Q&A session took place at the 2020 Ultrapure Micro annual conference. It was a part of the Ultrapure Water Production track, and included speakers from the UPW Process Optimization 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 Airborne Molecular Contamination (AMC) and High Purity Gases Control session.

This presentation was given at the Ultrapure Micro 2020 annual conference. It was presented in the Water Management and Wastewater Treatment track, as part of the Wastewater Treatment and Environmental Compliance 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 UPW Contamination Control session.