Ion beam etching (IBE) is a very promising technique in microelectronics because of its capability to etch small patterns with a high resolution and inert materials. In this study, the angular incidence of an argon ion beam on the etch rate and uniformity is discussed in the case of several materials often used in microelectronics. The capability of the IBE technique to etch multilayered stack samples with positive anisotropic profiles was demonstrated on TiNiAu, TiNiCuAu, BST and PZT. Two typical defects involved in IBE processing (fences and not etched pattern foots) due to shadow masking and redeposition effect, are explained and solutions are presented to avoid them. Deep IBE was performed on GaN with an etch depth as high as 10 μm, using a 8 μm thick SiO 2 mask. The etching of other mask materials, such as TiN, was investigated in order to improve the selectivity. Using a TiN mask, a selectivity to GaN as high as 5 is reported. Finally, the etch rate enhancement needed for deep etching was studied.

The thermal atomic layer deposition (ThALD) of yttrium oxide (Y2O3) was developed using the newly designed, liquid precursor, Y(EtCp)2(iPr2-amd), as the yttrium source in combination with different oxygen sources, such as ozone, water and even molecular oxygen. Saturation was observed for the growth of the Y2O3 films within an ALD window of 300 to 450 °C and a growth per cycle (GPC) up to 1.1 Å. The resulting Y2O3 films possess a smooth and crystalline structure, while avoiding any carbon and nitrogen contamination, as observed by X-ray photoelectron spectroscopy (XPS). The films showed strong resistance to fluorine-containing plasma, outperforming other resistant materials, such as silicon oxide, silicon nitride and alumina. Interestingly, the hydrophilic character exhibited by the film could be switched to hydrophobic after exposure to air, with water contact angles exceeding 90°. After annealing under N2 flow at 600 °C for 4 min, the hydrophobicity was lost, but proved recoverable after prolonged air exposure or intentional hydrocarbon exposure. The origin of these changes in hydrophobicity was examined.

En lien indissociable de laquestion géopolitique et du rapport à « l’Ouest collectif » euro-atlantique, laguerre d’invasion de l’Ukraine par la Russie a une dimension manifeste d’exacerbationde la gouvernementalité poutinienne, dans laquelle se précise la redéfinitionen cours de l’état de guerre – permanent ? – comme nouvelle « raison d’État »en Russie. Pendant vingt ans, le pouvoir du gouvernement de Vladimir Poutine atenu grâce à la démobilisation de la population russe, incitée à nes’intéresser ni aux guerres ni à la chose publique en général. Mais le régimeopère aujourd’hui un basculement total, en demandant à la société de se levercomme un seul homme et de consentir à de grands sacrifices. À n’en pointdouter, le poutinisme est aujourd’hui à un point de bascule et demandera deplus en plus à sa population. Une forme de « restalinisation partielle » desrapports entre l’État et la société est en marche en Russie. Les effets en sontaussi larges que profonds.

We report the preparation of nanomasks for silicon plasma etching, which is not based on full top-down approaches such as conventional lithographic process. We used laterally phase separated polymers thin films (30 to 100 nm thick) obtained from immiscible polymer blends of poly(styrene) PS and poly(lactide) PLA, PS being the major component, spin-coated onto silicon substrates. Despite the high incompatibility of the two polymers, submicronic domains were obtained in the film. The selective extraction of the minor component (PLA) led to the formation of a perforated layer of PS at the top of the silicon substrate, and was used as a mask for the selective etching of the silicon. For that purpose, we used a cryogenic etching process where the silicon substrate was cooled at a cryogenic temperature (∼ -120°C) and exposed to a monocyclic SF6/O2 plasma. It was possible to etch anisotropic profiles with vertical sidewalls and minimal defects. Etched feature with an aspect ratio of 7 were obtained in these conditions. We determined that the selectivity of etching (Si/PS) was 11:1, with a silicon etching rate of 0.8 µm/min. The selectivity of these masks was further increased when using the inorganic replicas of the polymer template (50:1) or with chemical modifications of the PS by RuO4 (80:1), allowing for increased aspect ratio etched features (up to 20 in the latter case). Optimized etching processes (such as STiGer process) were also used in order to improve the reproducibility and robustness of the method.