Nanomaterials in nanoelectronics
The semiconductor industry uses a growing variety of materials, as companies seek to further improve devices’ performance to meet increasing market demand in a constant process of innovation. At present, there are more than 200 chemical compounds consisting of elements, such as silicon, germanium, copper, gold, hafnium, indium and many others, which are present in most computer and mobile phone chips. Understanding the properties of these innovative materials and nanoforms, and how they behave in living systems, such as the human body, often comes years after the materials have been introduced in manufacturing. Such an inherent uncertainty brings about multiple challenges in the governance of the occupational and environmental risks. This is a common challenge for many technology-intensive sectors and it requires a systematic risk reduction approach.
Communication of risk, competences development, and training
Definite needs for competences development were established in terms of informing about the physicochemical properties of nanomaterials, a dedicated nanotoxicology knowledge base, and about the limitations of the traditional occupational chemical risk assessment. To meet these needs, the project composed nanosafety training packages, as one of its major outcomes. The project partners Tyndall, CEA and Imec composed three dedicated training courses focusing on semiconductor industry processes and the clean room environment. The topics of the training are as follows:
Introduction to nanomaterials in nanoelectronics
This is an induction training package for technical personnel – first-time users nanomaterials with no prior experience. The aim of the package is to increase awareness about general properties of engineered nanomaterials (ENMs) and use of EMNs in semiconductor processes, such as the chemical mechanical planarization (CMP) processes. CMP was selected because at present it is the best-understood process in terms of emission measurements and exposure assessment (WP3). The specific learning objectives are to:
- Give an overview of hazards and risks associated with nanomaterials
- Provide basic knowledge about nanomaterials, their properties, and general applications
- Give an overview of available protective/preventive measures for risk mitigation
The training package was designed for operators and maintenance staff working in the semiconductor sector. It was assumed that the recipients of the training had no prior experience of working with nanomaterials.
The specific emphasis on semiconductor process safety makes this training package unique and different from other nanosafety-related packages already developed by other projects, which cover a wide range of sectors and applications and are, therefore, less specific in terms of their safety policies recommendations.
- Societal and regulatory issues
- Properties of ENM
- Primer on toxicology
- Risk assessment
- Focus on the semiconductor industry
- Future materials for ICT
- General principles of risk prevention
- Reduction of potential exposure
- Collective protection
- Personal protection
- Operational control
- Environmental release and fate
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How can we perform a risk assessment of operations involving ENM?
The NanoStreeM consortium developed a training package for safety professionals to aid in their formative education concerning the properties of nanomaterials and available risk assessment methodologies.
At present, there are significant information gaps about properties of nanomaterials and they preclude the typical chemical safety risk assessment methodologies to be applied. Available public information is focused only on a very limited set of materials, while the safety data sheets fail to convey the information necessary to conduct a risk assessment. In such conditions, it is important to train engineers and researchers to understand the properties of nanomaterials and the methods to conduct risk assessments.
Unique properties of ENMs entail dependence of the toxic effects on the size and shape of the nanoparticle and not to unit mass. The toxic effects can be substantially modified by applied surface functionalization. Therefore, the current expert opinion agrees that conventional risk assessment tools have limited applicability to nanomaterials or nanoforms. At present, there are more than 30 risk state-of-the-art assessment tools providing quantitative and qualitative methodologies for risk assessment. Therefore, detailed guidance for risk assessment was produced. The applicability of the risk assessment guidance was evaluated by the industrial partners. The consortium has encountered several substantial gaps which impede recommended risk assessment tools.
NanoStreeM developed a three-tier approach for risk assessment
- Tier 0: Use of risk banding approaches to categorize risk: the ISO Standard ISO/TS 12901-2:2014 or StoffenManager Nano.
- Tier 1: Use of (semi) quantitative tools to give exposure estimated: NanoSafer, Consexpo and Advanced REACH Tool (ART)
- Tier 2: Use of detailed emission measurement data to check the conclusions of Tier 1.
The aim of the package is to increase awareness about properties of ENm, having an impact on safety assessments. The package is designed for safety professionals having experience in chemical safety or semiconductor process safety. The specifics of nanomaterials and the present regulatory framework in the EU are emphasized. The training is based on the ISO TR 12802-2 and ISO/TS 12901-2:2014. The package exemplifies the NanoStreeM approach and discusses also measurement tools for airborne nanoparticle emissions as a relevant use case.
- Morphology of ENM and physicochemical properties
- Regulatory frameworks
- Data gaps in nanosafety
- Elements of the risk assessment
- Emission measurement and NP characterization tools
- Risk banding approaches
- The NanoStreeM risk tiered assessment framework
- Emission measurement strategies
The slides are available under Creative Commons with attribution and no derivative works.
Finally, the consortium developed a “Train the trainer” guideline for deployment of the training.