Study on particle behavior in ultrapure water

UF even withstands episodic increase of particle numbers in the feed (e.g., caused by conditioning of ion-exchange resins) without negative effects for water quality and service lifetime. Such a particle challenge typically involves high concentrations of ~10-nanometer (nm) particles. On the other hand, current on-line particle counters approach their lower detection limit at about 10nm. Large numbers of particles nearby and below this limit remain undetected. Hence, the integrity of a UF membrane is essential to keep these small particles under control; it can hardly be evaluated by comparing particle counts upstream and downstream. Therefore, better test methods are needed to identify membrane damages, and to decide on service life and replacement of UF membranes.

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 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.

In recent years, with the development of the semiconductor manufacturing process, ultrapure water (UPW) used to wash semiconductor devices have required high purity. In particular, particles in UPW are strictly controlled. Our 10 nm SEM analysis can measure 10 nm particles, which was previously impossible. This article presents the results of measuring 10 nm particles in the existing ultrapure water system. We clarified the behaviour (including generation sources and compositions) of 10 nm particles in ultrapure water systems in order to optimize and enhance. 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.

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 Contamination Control 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 Critical Particle Monitoring session.

This presentation was given at the Ultrapure Micro 2019 annual conference. It was presented during the Learning Series, as part of the Ultrapure Water Production track.