Photolithography, the process used to fabricate integrated circuits, is the key enabler and driver for the semiconductor industry for device scaling. The miniaturization of feature sizes has been achieved mainly by shortening the wavelength of exposure tools by evolutionary advances in nanolithography and in turn by similar advances in photoresist technology. Today the shortening wavelength trend is continuing with the aim of achieving 1x nm resolution by the deployment of the extreme ultraviolet lithography (EUVL) using exposure light wavelength of 13.5 nm. Current photoresist platforms have performance limitations in resolution, line width roughness and sensitivity (RLS) and fundamental studies are needed to reach the material performance requirements for EUVL technology.
The project aims to offer possible better solutions to the trade-off RLS relationship for conventional and nonconventional chemical platforms designed for the EUV radiation chemistry. The target photoresists will be the existing chemically amplified resists and novel concept of resists delivered by material suppliers and/or from research institutes working on the design and synthesis of new EUV resist materials.
This project will run under a Marie Skłodowska-Curie Innovative Training Network (ITN) focused on low energy electron driven chemistry for the advances of emerging nano-fabrication methods (ELENA). Overall ELENA aims 1) to increase the understanding of the fundamental processes underpinning the innovative nanoscale fabrication techniques (as EUVL) and translate this knowledge into the design of precursor molecules specifically for EUV resists, such that EUVL may be further optimized in performance, with the ultimate goal of making them commercially competitive, 2) to train a new generation of early stage researchers (ESRs) with a fundamental understanding of the physics and chemistry underpinning the EUVL whilst applying this knowledge to the needs of the nanotechnology industry. Specifically for EUVL, the main objective is to help establish a funded understanding of the different mechanisms of interaction among the resist chemistry, the EUV radiation and the boundary lithographic process conditions. On the long run, in conjunction with the fundamentals of electron induced chemistry EUV studies from the Institute for Applied and Physical Chemistry of University of Bremen (UBre), with the fundamental investigations on electron-initiated reactions of novel precursors relevant to EUVL from the Institute of Material Chemistry of Vienna University of Technology (TUV), along with theoretical modelling of complex molecular systems in collaboration with MBN Research Center in Germany (MBN-RC), it is expected this understanding to contribute to a rational design of superior EUV resists relevant for the scaling device roadmap of the semiconductor industry.
The RLS of novel resists will be investigated on coated bare silicon wafer exposed by the EUV tool using the appropriate process conditions (material, optical conditions and patterning size) in line with the EUVL technology roadmap for 1x nm device scaling. The RLS characterization of the photo material will be done mainly using an advanced scanning electron microscope. Particular attention will be put on one hand to the potential correlation between the RLS and the material design (polymer type, acid generators, absorption and electron yield, molecular/polymer size, acid amplification, acid diffusion) and on the other hand to the potential correlation between the RLS and the resist process conditions (under layer, post applied bake, post exposure bake, development. rinse).
You will be trained in commercial and entrepreneurial skills necessary to bring such research from the laboratory to the commercial arena. You will work together with a team of lithography specialists within an international environment using advanced tools at the leading edge technology. You will interact with the resist materials vendors as well as the various university groups working on these materials.
Your experimental work will be carry out in a modern 300 mm semiconductor cleanroom using the lithography clusters to coat and expose silicon wafers and metrology tools for the material characterization. The results of your research will be presented to ELENA partners, imec partners and either published at international conferences and/or in peer reviewed journals.
The topic is best suited for students with a degree in chemistry, nano-technology, materials science with fundamental understanding of x-ray physics and light-matter interaction.
Type of work
15% training, 15% literature study, 10% simulation work, 60% for preparation and execution of experiments + data analysis. Further, three secondments are planned during the project: 3 months at TUV (M10-12) to work with the preparation and handling of EUVL resist formulations of homogeneously dispersible clusters and get acquainted with the fundamentals of inorganic synthesis. 4 months at UBre (M23-M26) to study fundamentals of electron induced chemistry in EUV material components under controlled UHV conditions, 3 months at MBN-RC (33-35) for theoretical modelling of complex molecular systems.
Supervisor: Stefan De Gendt
Daily advisor: Danilo De Simone
This project is not subject to the April 15th, 2017 application deadline but is open for immediate application.
When you apply for this PhD project, mention the following reference code in the imec application form: ref. 1612-ELENA.