QUB- Mechanical and Aerospace Engineering International PhD Project
2015-2016
Title: Modelling and simulation of diamond wire sawing of silicon wafers
Project description:
This project is open to International applicants and seek bright candidates to work towards their
PhD at Queen’s University of Belfast, UK supported by a Paris based world leader in solar energy.
The driver of modern electronic gadgets is Moore’s Law, which says that the count of transistors on
a chip doubles every two years. This drive creates pressing need for innovative manufacturing
methods to fabricate silicon which has continued to remain a wonder material for electronics.
Historically, Loose abrasive slurry sawing (LSS) has remained most popular process for
producing photovoltaic (PV) silicon wafers but environmental considerations and high productivity
have pushed the usage of newly emerging technology known as fixed abrasive diamond wire
sawing (DWS).
A typical DWS process, entails sawing of big cylindrical ingots of silicon (on a preferred crystal
orientation) using a series of parallel wires. The surface quality of the cut wafers attained by this
method inevitably results in the formation of undesirable micro-fracture and cracks on the cut
surface of silicon. Not much is understood about the DWS process as the process is still in infancy.
Therefore, a significant opportunity exists in developing the DWS production process.
Development of a scientific understanding of the DWS process will improve the yield and reduce
the manufacturing costs, as it contributes upto 20% of the wafer manufacturing costs. In order to
understand the process, the project will take a simulation based approach involving the use of finite
element analysis (FEA) and molecular dynamics simulation (MDS) using high-performance
computing (HPC) facilities involving novel way of describing the material behaviour of silicon and
carbon. As an important research activity, the design of diamond particles which are mounted on
the wire in particular their shape, size and distribution is an intriguing task to enhance overall
sawing performance. Eventually the aims of this project are to predict:
 the material removal process as a function of speed of cut and geometry of wire (including
its diameter, and size of and distribution of diamond particles) and process parameters like
load
 sub-surface damage in accordance with above
 Exploit the use of an appropriate coolant (lubricity).
Accordingly, the following work packages will be executed:
WP1 (1 year): Development of baseline models of the DWS process using FEA and MD on generic
wire geometry. Different conditions (size and distribution) and orientation of cut will be considered
and correlated with the velocity and load on the wire in influencing the cutting
WP2 (2nd year): Accounting for the wear of diamond and sub-surface damage and to validate the
model including integration of FEA and MD findings.
WP3 (3rd year): Development of predictive optimisation models to assist in cost saving operations
and draw the scientific specifications for the wire performance in line with experimental data.
Key skills required for the post:
Applicants must have a 2:1 honours degree in physics/materials science/mechanical engineering, or any
other equivalent qualification. Candidates should be able to demonstrate that they are highly motivated, have
excellent communication skills, and excellent modelling skills: be able to drive the project by understanding
the industrial needs and using their own initiatives. The project offers a lot of opportunity to International
travel and hence candidate with good mobility are desirable.
Key transferable skills that will be developed during the PhD:
The researcher will complete their PhD within a cohort of students researching design and simulation. The
researcher will have access to the experimental suite of the world leading industry in silicon PV cells, be in
continual contact with their R&D engineers and will undergo a secondment at their site. The researcher will
also present their work to project partners at regular technical meetings and workshops. Recent PhD
graduates have gone on to take up influential technical positions in leading UK and international engineering
companies and so this seems to be an ideal opportunity to place your career on the right track.
First/Lead Supervisor and Dr Saurav Goel , Tel: +44 (0)28 9097 5625, Email S.GOEL@qub.ac.uk
their contact details
Second Supervisor
their contact details:
and
Funding of the project
Dr Adrian Murphy, Tel: +44 (0)28 9097 4095,
Linked to DTC?
The studentship covers the full tuition fees and a tax-free stipend of up to
£18,500 per annum (£17,000 cash/annum and to earn a further £1,500 per
annum by undertaking part time teaching) for a period of three and half
years.
No
Project start date and end
date
September 2016 to February 2020 (early completion will lead to early
graduation)