Thin films and patterning response in EUV device scaling

 

EUV lithography patterning and subsequent etching steps rely on the thin films stack that is used for pattern transfer into the final layer of interest. This stack has been engineered for both lithographic needs, as well as an optimized etch process in terms of selectivity and profile. However, the impact of the properties of this film stack on the patterning outcome are not well characterized or understood. The role of individual film material properties and interactions between layers need to be understood in relation to the outcomes of EUV patterning post lithography and post etch transfer (i.e., critical dimension (CD) control and its uniformity across the wafer, the line-edge roughness (LER) and line-width roughness (LWR), and the defectivity). The fundamental understanding of material properties and their relationship to EUV patterning outcomes will help drive advancements in High-NA innovation.

 

As part of this PhD work, you will work to define and systematically study the material properties that induce a change in the patterning outcome. You will quantify the impact of surface and bulk material properties on the resulting patterning metrics at lithography and etch levels. You will use advanced semiconductor processing tools in imec’s 300mm clean room, as well as characterization techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray reflectivity (XRR), Time-of-Flight Secondary Ion Mass Spectrometry (TOFSIMS), and Atomic force microscopy (AFM). You will formulate directions on material design toward device scaling and material patterning strategy from a thin films perspective. You will also have the opportunity to work with  a team of researchers with vast experience on these topics that will be able to offer guidance and feedback. 

 

[1] M. van de Kerkhof et al., Solid State Electron 155, p20 (2019)

[2] Moore et al, IEEE Spectrum 55-1, p46 (2018)