Total X-Ray Fluorescence (TXRF) is a non-destructive technique for the characterization of metallic contaminants on bare silicon wafers. TXRF is sensible to roughness leading to a diffraction phenomenon. In this study, the effects of roughness on TXRF analysis were evaluated with various rough silicon wafers produced by microelectronic processes of grinding, wet cleaning and chemical mechanical polishing. TXRF parameters rise as roughness increases, starting from 3 nm RMS (Root Mean Square) roughness. On spectra, characteristic Si (silicon wafer) and W (TXRF anode) peaks widen. Secondary peaks, sum/escape peaks appear, inducing interferences with Al, Cu, Zn and background noise increases as well. Through intentionally contaminated grinded wafers (RMS 12 nm) by spin-coating at selected concentrations, it was observed that most of the elements are quantified at 1 × 1012 at/cm2. At concentrations of 1 × 1010 at/cm2 and 1 × 1011 at/cm2, only few elements are quantified due to the elevated background noise and interferences.

Due to the increasing number of application fields using lithium compounds in the microelectronics sector, it is necessary to investigate the contamination influence and the effects of lithium on silicon and silicon oxide. To be able to use lithium in a controlled manner in complementary metal-oxide-semiconductor clean room environments, the various diffusion effects during an important process in semiconductor manufacturing, the thermal oxidation of silicon to form silicon oxide, are investigated herein. This includes the diffusion within the wafer, between wafers, and into the furnace environment. For this purpose, wafers are intentionally contaminated, oxidized, and then analyzed with vapor phase decomposition inductively coupled plasma mass spectrometry. The results of this study are correlated with typical contamination levels in state-of-the-art cleanroom facilities to enable classifications of the results for the semiconductor sector. Furthermore, the effect on the growth rate and uniformity of silicon oxide is evaluated by ellipsometry and topography measurements. Finally, electrical measurements of the oxide layer have shown that there is a significant influence on the silicon oxide quality, meaning that lithium can have a detrimental effect on devices. As the potential applications of lithium in the semiconductor sector are increasing, this study creates the basis for the assessment of its impact. Therefore, the diffusion within the wafer, between wafers, and into the environment during the thermal oxidation of silicon are studied. Furthermore, the effects on the growth rate, uniformity, and quality of the silicon oxide are investigated.image (c) 2024 WILEY-VCH GmbH

This paper offers a preliminary study for the analysis of metallic contamination on front-end patterned wafers obtained by two different techniques based on the etching of the whole patterns, LPD-Bulk and VPD-Bulk coupled with an ICPMS. To elaborate the analysis of patterned wafers, methods were first verified and optimised on reference Si wafers. Both techniques are complementary methods for the etching of wafers. LPD-Bulk enables a fast etching of several micrometres of Si but with less precision than VPD-Bulk, which is more adapted for the etching of layers thinner than 1 micrometre. The intentional contamination in SC1 and H2O bath of monitoring wafers showed that contamination in H2O is better controlled due to the absence of chemical reactions, competition between oxidation and etching processes occurring during SC1. And diffusion of contaminants at the tested temperatures from 20°C to 80°C, does not occur. Heat treatment should be applied to allow the diffusion of metallic contaminants in the bulk of the wafers.

This paper compares the contamination monitoring of the three largest microelectronics research organizations in Europe, CEA-Leti, imec and Fraunhofer. The aim is to align the semiconductor infrastructure of the three research institutes to accelerate the supply to European industry for disruptive chip processing. To offer advanced edge AI systems with novel non-volatile memory components, integration into state-of-the-art semiconductor fabrication production flow must be validated. For this, the contamination monitoring is an essential aspect. Metallic impurities can have a major impact on expensive and complex microelectronic process flows. Knowing this, it is important to avoid contamination of process lines. In order to benefit from the combined infrastructure, expertise and individual competences, the feasibility of wafer loops needs to be investigated. Through a technical comparison and a practical analysis of potential cross-contaminations, the correlation of the contamination measurement 104results of the research institutes is investigated. The results demonstrate that the three institutes are able to analyse metallic contamination with comparable Lower Limits of Detection (LLDs). This result sets the foundations for smooth and fast wafer exchange for current and future needs, potentially not only within research institutes as well as with industrial and foundry partners. The present work pays attention to both surface and bevel contamination. The latter requires very specific contamination collection which was also compared. Nevertheless, some challenges need to be addressed in the future to advance and accurate contamination monitoring.

Recent research efforts have gone into formalizing and standardizing the Safe by Design process of nanomaterials. This usually results in a structured and (most often) sequential approach deliberately putting the focus on hazard and exposure issues regarding the nanomaterial itself in a bottom-up progression of material development. However, this general strategy lacks flexibility. Within the project SERENADE, a case study examining photocatalytic paint failed to validate the generally accepted Safe by Design scheme. This example examined the product (paint in this case) rather than the nanomaterials it contains. It was found that the essential parameters, namely product specification and functionality, failed to fit into a rigid bottom-up approach and indicated the need for alternative Safe by Design strategies. (C) 2021 Elsevier Ltd. All rights reserved.

Developing safe nanomaterials has become a major concern in all the industry sectors using advanced materials. However, there are very few initiatives addressing this issue. The SERENADE project, with its long-term funding scheme, provided a unique opportunity to foster a coordinated, yet diverse approach to investigate the safe-by-design development of nanomaterials in a variety of application fields, using a targeted set of inter-disciplinary case studies. The originality of the approach was to cover as many multiple technology readiness levels (TRLs) and life cycle stages as possible, combined with shared hazard and end-of-life assessments in an effort towards a (more) comprehensive and resource driven research.

Stabilization and coating with bio-inspired ligands of TiO2 nanoparticles for the development of safer-by-design photocatalytic paints.

This study was designed to optimise an analytical method for characterising TiO2 nanoparticles (NPs) in food additives and pharmaceuticals by inductively coupled plasma-mass spectrometry in single particle mode (spICP-MS). Several parameters, including transport efficiency (TE), were assessed and optimised using the NM-100 reference material. We found that self-aspiration for sample intake and use of the concentration-based method for TE was optimal for characterising TiO2 NPs. No spectral interference was observed with either 49Ti or 48Ti isotopes. The optimised Excel spreadsheet developed for this study not only provided additional parameters but gave results closer to the NM-100 reference value than the ICP-MS software. The method was then applied to the analysis of a selection of food samples and pharmaceuticals. The average diameter of TiO2 particles ranged from 86 to 179 nm in the food samples and from 131 to 197 nm in the pharmaceuticals, while the nanoparticular fraction was between 19 and 68% in food, and between 13 and 45% in pharmaceuticals.

This study aims at the optimization of a novel analytical approach for the characterization of TiO2 nanoparticles (NPs) in food additives by asymmetric-flow field-flow fractionation (AF4) in tandem with inductively coupled plasma-mass spectrometry (ICP-MS). For this purpose, the influence of pH, ionic strength, and of various surfactants on the zeta potential (ZP) of both NPs and the AF4 membrane was assessed. Results show that the ionic strength has a considerable influence on the membrane ZP and consequently on the NPs’ recovery from the AF4 membrane during their separation. Therefore, ZP of the membrane can be controlled by varying the ionic strength of the analyzed NP suspension to obtain the same electrostatic charge as the NPs and hence minimizing their adsorption on the membrane. It was also confirmed that the nature of the surfactant affects mostly NP dispersion quality than on the recovery rate. Among the surfactant investigated, ultrapure water and FL-70 provided the lowest measured gyration diameter despite the presence of aggregates. Additional parameters such as the use of different phases for the NP dispersion and eluent composition could be taken into consideration for future experiments.

Due to their unique optical properties, quantum dots (QDs) are used in a number of optoelectronic devices and are forecasted to be used in the near future for biomedical applications. The most popular QD composition consists of cadmium selenide (CdSe) or cadmium telluride (CdTe), which has been shown to pose health risks due to the release of toxic cadmium (Cd) ions. Due to similar optical properties but lower intrinsic toxicity, indium phosphide (InP) QDs have been proposed as a safer alternative. Nevertheless, investigations regarding their safety and possible toxicological effects are still in their infancy.

Photocatalytic materials are a potentially effective remediation technology for indoor air purification.

With the goal to improve their photostability, InP-based QDs are passivated with three types of inorganic shells, namely (i) a gradient ZnSexS1-x shell, (ii) an additional ZnS shell on top of the gradient shell with two different thicknesses (core/shell/shell, CSS), (iii) an alumina coating on top of ZnS. All three systems have photoluminescence quantum yields (PLQY) > 50% and similar PL decay times (64-67 ns). To assess their photostability they are incorporated into a transparent poly (methyl methacrylate) (PMMA) matrix and exposed to continuous irradiation with simulated sunlight in a climate chamber. The alumina coated core/shell system exhibits the highest stability in terms of PLQY retention as well as the lowest shift of the PL maximum and lowest increase of the PL linewidth, followed by the CSS QDs and finally the gradient shell system. By means of XPS studies we identify the degradation of the ZnS outer layer and concomitant oxidation of the emissive InZnP core as the main origins of degradation in the gradient structure. These modifications do not occur in the case of the alumina-capped sample, which exhibits excellent chemical stability. The gradient shell and CSS systems could be transferred to the aqueous phase using surface ligand exchange with penicillamine. Cytotoxicity studies on human primary keratinocytes revealed that exposure for 24 h to 6.25-100 nM of QDs did not affect cell viability. However, a trend toward reduced cell proliferation is observed for higher concentrations of gradient shell and CSS QDs with a thin ZnS shell, while CSS QDs with a thicker ZnS shell do not exhibit any impact.

Photocatalytic paints based on titanium dioxide (TiO2) nanoparticles represent a promising treatment technology for cleaning the air at our dwellings. A few studies have shown that instead of elimination of harmful indoor air pollutants the production of carbonyl compounds occurs from the photocatalytic paints. Herein, we report unexpectedly high concentrations of volatile organic compounds (VOCs) released upon irradiation of photocatalytic paints which are meant to clean the air at our dwellings. The concentrations of the VOCs were measured continuously and online by PTR-ToF-MS (Proton Transfer Reaction-Time of Flight-Mass Spectrometry) connected to a well-established flow tube photoreactor. The PTR-ToF-MS analysis revealed the presence of 52 ions in the mass range between 20 and 490 amu, among which 43 have been identified. In particular very high emission rates were estimated of two relevant indoor air pollutants, formaldehyde and acetaldehyde as 355 μg h-1 and 257 μg h-1 for 1 m2, respectively. We suggest a detailed reaction mechanism responsible for the production of these harmful indoor air pollutants (formaldehyde and acetaldehyde, among the others). The hydroxyl radicals (OH) formed upon activation of TiO2, react with the organic constituent (butyl acrylate and vinyl acetate) of the paint binder lead to generation of an important number of organic compounds. We demonstrate that the TiO2 quantity and the organic content of the binder is of paramount importance with respect to the formation of VOCs, which should be considered for future optimization of this air remediation technology based on TiO2 nanoparticles.

Polythiol molecules dissolve silver nanoparticles with kinetic rates that increase with the number of thiols per molecule and their pre-orientation.

Sunscreens are of emerging concern regarding both human and environmental health. While TiO2 nanoparticles used as UV-blockers may offer a safer alternative to organic filters, their fate and impact and resulting regulation are still under consideration, largely related to the potential risk of nanotechnology-based products. After leaving the skin either through bathing or cleaning, the TiO2 nanomaterials contained in the sunscreen can be released into rivers, lakes, sea shores, and/or sewage treatment plants. Their fate and impact in these different systems is largely determined by the surface properties, i.e. the coating type and lifetime. This project aims to develop the eco-design of sunscreens through the minimization of risks associated with nanomaterials incorporated into the formulation. All stages of the cream life cycle must be considered in this light, from its manufacture to its end of life, through its use by the consumer and its impact on the exposed environment. By considering each development stage of the sunscreen, from the choice of UV-blocker and its integration into a cosmetic formulation, to the knowledge of the risk involved in this choice all along the product lifecycle, an eco-design approach can be achieved and risk can be minimized. The present work combines industrial companies specialising in cosmetic formulation with academic research experts in the fields of exposure, toxicity and lifecycle assessment. Sunscreen fabrication, risk for the consumer by dermal exposure, risk for the direct aquatic environment and risk related to the end of life of the product are as many key steps of the sunscreen lifecycle that were investigated in this project.

The release of Ag(i) from silver nanoparticles (AgNPs) unintentionally spread in the environment is suspected to impair some key biological functions. In comparison with AgNO3, in-depth investigations were carried out into the interactions between citrate-coated AgNPs (20 nm) and two metalloproteins, intracellular metallothionein 1 (MT1) and plasmatic ceruloplasmin (Cp), both involved in metal homeostasis. These were chosen for their physiological relevance and the diversity of their various native metals bound because of thiol groups and/or their structural differences. Transmission electron microscopy (TEM), and dynamic light scattering (DLS), UV-vis and circular dichroism (CD) spectroscopies were used to study the effects of such intricate interactions on AgNP dissolution and proteins in terms of metal exchanges and structural modifications. The isolation of the different populations formed together with on-line quantifications of their metal content were performed by asymmetrical flow field-flow fractionation (AF4) linked to inductively coupled plasma mass spectrometry (ICP-MS). For the 2 proteins, Ag(i) dissolved from the AgNPs, substituted for the native metal, to different extents and with different types of dynamics for the corona formed: the MT1 rapidly surrounded the AgNPs with the transient reticulate corona thus promoting their dissolution associated with the metal substitution, whereas the Cp established a more stable layer around the AgNPs, with a limited substitution of Cu and a decrease in its ferroxidase activity. The accessibility and lability of the metal binding sites inside these proteins and their relative affinities for Ag(i) are discussed, taking into account the structural characteristics of the proteins.

Among cosmetics and personal care products, sunscreen products are of emerging concern regarding both human and environmental health. The fate and impact of mineral nanoparticulate UV-blockers, such as TiO2 nanomaterials, is under consideration from a regulatory perspective due to their potential impact. Here we present the first result of the Eco-SUN research program aimed at developing the eco-design of sunscreens through the minimization of risks associated with nanomaterials incorporated into the formulation. Different stages of the cream lifecycle are considered from its manufacture to its end of life, through its use by the consumer and its impact on the exposed environments. Reducing the potential release and / or toxicity of the nanomaterial from the cream is a decisive criterion for its ecodesign. Different relevant TiO2 UV-blockers have been selected to integrate a typical w/o formulation as case studies. The resulting sunscreens were characterised in terms of nanomaterial localisation, sun protection factor and photo-passivation. The risk for the consumer by dermal exposure will be assessed using skin biopsies, and evaluating inflammation and skin penetration. The risk for the aquatic environment directly exposed will be assessed both in terms of exposure and hazard. The release of nanomaterials from the sunscreen upon normal usage was studied in the laboratory through a simulated aging procedure. Two biological models, sea urchin and coral colonies, were selected as relevant endpoints to assess the marine ecotoxicity of the by-products formed. Finally, the risk related to the end of life of the sunscreen through the removal with cleaning water followed by drainage to sewage treatment plants will be evaluated by considering the scenarios of nanomaterial concentration in sewage sludge later spread as fertilizer in agriculture.

The structure of inorganic fillers dispersed in proton exchange membranes for fuel cell (PEMFC) was investigated by X-ray scattering and electron microscopy. The hybrid membranes have been obtained by an in situ precipitation of zirconium Phosphate (alpha-ZrP) particles within a perfluorosulfonated ionomer membrane (Nafion). An extended angular range in the scattering experiments was covered in order to analyze simultaneously the crystalline structure of the particles, their shape and their size. At wide angles, the scattering peaks characteristic of the presence of (alpha-ZrP have been observed and the width analysis of the scattering peak corresponding to the stacking of (alpha-ZrP layers suggests a packing of 10-13 alpha-ZrP layers. The small angle spectra reveal that the structure of the membrane is not modified by the introduction of inorganic species and the excess of scattering intensity due to inorganic particles is well reproduced by the form factor of oblate ellipsoids, with a semimajor axis length of about 280 angstrom and a semiminor axis length of about 35 angstrom. These results are confirmed by high-resolution scanning electron microscopy.