Are you an engineer who wants to contribute to high-tech, state-of-the-art modelling of microscopic wear of silicon during wafer handling? We are looking for an outstanding and enthusiastic PhD candidate, with a strong computational mechanics profile of excellence.ContextThe yield of many manufacturing processes of micro- and nanoscale substrates depends highly on their cleanliness. Reduction of contaminating particles improves the overall efficiency and quality, thereby enabling the creation of larger structured substrates. Investing in the prevention of wear particles generation is a way to tackle this issue directly at the source, which is particularly relevant for wafer handling.
Silicon is a very complex material, undergoing multiple phase transformation, with some phases showing extensive plastic deformation, during mechanical loading and contact. The generation of particles is rooted in the complex fracture events spanning the various phases of silicon in various 3D stress configurations. A predictive model should properly account for the complex physics, damage and fracture. The loading conditions in contact and scratching are equally complex and need to be properly accounted for as well.
PhD projectThe objective of this PhD project is to achieve predictive simulations of silicon particle detachment under contact conditions, enabling a quantitative assessment of the governing influence factors and possible mitigation routes to control the detachment process. To achieve this goal, a physically-based extension of an existing particle-based method (implemented in LAMMPS) is required to account for transformation plasticity, damage and fracture, which is the ultimate objective of this project.
Starting from a preliminary particle-continuum based model for silicon, the following extensions and improvements need to be made:
- Improved constitutive model for silicon governing its mechanical response and damage upon strain-induced phase transformations
- Large-scale plasticity mechanisms leading to chip formation
- Develop bond-based fracture criteria for the silicon phases
- Implement a damage model in the particle-based continuum bond method and validate the model on the basis of experimental results
- Extend contact formulation to account for friction
- Incorporate the crystalline anisotropy in the particle-continuum formulation
The modelling framework above will strongly depend on experimental input for the material characterization and validation. The interaction between the modelling project and a parallel experimental project, focused on measuring particle generation in silicon wafers is therefore essential.
Section Mechanics of MaterialsYou will work in the section of Mechanics of Materials (MoM) (
www.tue.nl/mechmat) at the department of Mechanical Engineering of Eindhoven University of Technology (TU/e). The MoM section is recognized worldwide for its high-level research on experimental analysis, theoretical understanding and predictive modelling of complex mechanical behavior in engineering materials at different length scales (e.g, plasticity, damage, fracture), which emerges from the physics and mechanics of the underlying multi-phase microstructure. An integrated numerical-experimental approach is generally adopted for this goal. A state-of-the-art computing infrastructure is in place for the numerical work in this project.