Filter Media Removal Characteristics in the Low nm Range

The focal point of this article is the protection of RO membranes used to produce feedwater for the deionization process.

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

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.

This presentation was given as part of the Ultrapure Micro 2021 annual conference. It was given as part of the airborne molecular contamination (AMC) and high purity gases control strand.

This presentation was given as part of the Ultrapure Micro 2021 annual conference. It was given as part of the airborne molecular contamination (AMC) and high purity gases control strand.

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

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

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 deliberates how it has become possible to test any microfine filter in real time, and in its actual conditions of use. For such testing to be possible it is vital to be able to obtain two particle-counting instruments matched for particle detection over a range of particle sizes. This attribute of matched detection appears to be possible with the acoustic method of detecting particles, and not commonly available with optical particle counters. This article was originally published in the Ultrapure Micro Journal in November 2017.

Nanoparticle contamination of ultrapure water (UPW) for microelectronics fabrication is expected to significantly decrease the yield and reliability of semiconductor devices. Tight nanoparticles control poses a technical and analytical challenge, especially in the particle size range down to a few nanometres. Most state-of-the-art online particle counters do not address the needs of advanced microelectronics manufacturing with critical particle sizes below 20 nm. Therefore, understanding of sources of nanoparticle contamination and strategies for control is limited. This study aims to profile nanoparticles ≥10 nm in a full-scale UPW polishing system after each process step using two novel particle measurement systems: an optical particle counter and an acoustic particle counter. For the first time, the performance of a whole UPW polishing system, including a Reverse Osmosis (RO) unit in terms of particle rejection, was investigated. Both particle counter instruments were evaluated with positive results. A statistical analysis was carried out to compare the significance of the particle counts achieved by the two different detection principles. Profiling throughout the UPW polishing system revealed that both instruments measure particle concentrations in the same range. The data is consistent and shows a clear trend: ion exchange mixed bed, Reverse Osmosis (RO) and ultrafiltration remove particles and represent sinks for nanoparticles ≥20 nm. The removal of nanoparticles between 10 nm and 20 nm is limited in this case however, especially for the final ultrafiltration. Scanning electron microscopy (SEM) with elemental analysis demonstrated that the particle chemistry was diverse. This indicates that different particle chemistries and particle properties might have influenced the particle counts. The results contribute to the advanced understanding of nanoparticle behaviour in UPW and provides more confidence in terms of monitoring at the lower particle range. This article was originally published in the Ultrapure Micro Journal in March 2019.