Physical characterization of ultra-thin photoresists for high-NA EUV lithography

​Over the last decades, the miniaturization of integrated circuits has been achieved by using shorter wavelength of light in optical lithography. Currently, extreme ultraviolet (EUV) light, with a wavelength of 13.5 nm, is the top-notch technology that enables smaller, more powerful chips. In the near future, however, we need to further improve the resolution by adopting high-numerical aperture EUV lithography. 

In anticipation of the high-NA technology, the focus is now shifted towards resist development. Due to of the continuous downscaling envisioned for high-NA technology, both photoresist film thicknesses (10 – 35 nm) and underlying film thicknesses (1 – 20 nm) are approaching the ultra-thin film regime, at and beyond the physical limits of bulk-phase behaviour where the interface interactions between the different layers become increasingly dominant. Another challenge is related to the inherent material characteristics that change in function of the film thickness. This project will explore the limitations of resists with respect to film thickness and focus on the characterization of changes that happen with going to the ultra-thin film regime necessary for high-NA. This work will significantly contribute to the understanding of resist interaction and changes with respect to film thickness and will lead to help the design of new photoresists for EUV lithography.

The applicant will work together with a team of lithography specialists within an international environment in a modern 300 mm semiconductor cleanroom using advanced tools at the leading-edge technology. The applican will learn and use spectroscopic ellipsometry, X-ray reflectivity, atomic force microscopy, and contact angle techniques to evaluate the physical properties of nanometric films: thickness, roughness, uniformity, density, surface energy. 

In addition, the candidate will learn the EUV lithographic process and will prepare and characterize patterned samples. This activity will include morphology chaarcterization by SEM (scanning electron microscope) for CD measurement  (critical dimension) and statistical analysis.

The ideal candidate should also have attitude towards teamwork in an international environment, enthusiasm and motivation. Because the working language is English, the applicant is expected to be able to speak and write fluently (≥ B2). Experience with Microsoft Office suite (Excel, Word, PowerPoint) is required. Knowledge of programming languages (C, VBA, Python) and/or programming software (MATLAB, Octave, Igor, Origin) is a plus.