Fundamental understanding and new solutions for photomasks enabling next generation lithography through simulation modeling, experimental characterization and imaging verification.
Optical lithography is one of the most challenging steps in device fabrication, as it is the key enabler to feature size reduction, leading to the ever smaller and faster devices. Optical lithography is the fundamental process in microchip fabrication that transfers the circuitry from the photomask onto a silicon wafer using a reduction optical system, which means that patterns on photomask (i.e., template) are larger than the final structures on wafer. Over the past decades, optical lithography has become increasingly complex as dimensions on the wafer continue to shrink. The imec lithography department focuses on sub-16nm devices, today’s smallest possible feature sizes or periodicities, using exposure light wavelengths of 193nm and 13.5nm. Consequently, the feature sizes on photomask are now approaching the dimensions of the optical wavelength, which generates new optical effects. These have to be understood, in order to accurately predict and control the imaging of the microchip circuitry.
The goal of this research is to examine innovative solutions and technologies for photomasks to enable next generation lithography. Fundamental learning on material behavior, through state-of-the-art metrology, will be combined with rigorous simulations to guide choices for new mask materials. This fundamental research will support future directions in advanced lithography and as such contribute to the continuous scaling in IC manufacturing industry. You will work together with a team of lithography specialists within an international environment with residents from imec’s partner companies. This topic allows for interdisciplinary collaborations between imec’s patterning, material and unit process departments. As such you will engage in the most advanced metrology and processing techniques of IC manufacturing and apply them to your topic.
This research topic involves an equal amount of simulation and experimental work. You will build a thorough understanding of the optical effects seen at photomask and how they transfer to wafer level using rigorous simulation software. Based on your modeling predictions and mask requirements you will experimentally characterize candidate mask materials using the facilities of imec’s state-of-the-art 300mm cleanroom. Your thorough screening of photomask solutions will be followed by the fabrication of an actual photomask with selected geometries or using new materials at one of the mask houses that are partner in the imec advanced patterning program. You will validate the imaging performance of the photomask candidate through sites that collaborate with imec and correlate the experimental data to the simulations for deeper fundamental insights. The results of your research will be presented to the imec partners, and are either published at international conferences, in peer reviewed journals or filed for patent.
Required background: engineering, physics, nano-technology, and/or materials science
Type of work: 10% literature study, 40% simulation work, 50% for preparation and execution of experiments + data analysis
Supervisor: Marc Heyns
Daily advisor: Vicky Philipsen
The reference code for this PhD position is STS1712-15. Mention this reference code on your application form.