Hidrodesulfuración del dibenzotiofeno y 4,6-dimetildibenzotiofeno sobre catalizadores NiMo, CoMo y NiW en estado sulfuro soportados en alúmina: efecto del galio como aditivo

Nowadays, the environmental regulations that impose very low sulfur content in diesel cuts have spurred research in hydrotreating catalysts. The commercial hydrodesulphurization (HDS) catalysts consist of an active phase of molybdenum or tungsten (Mo, W) promoted by nickel (Ni) or cobalt (Co) usually supported on alumina. Nevertheless, it has been recognized since the very first studies related to these solids (CoMo, NiMo, NiW/Al2O3) that alumina is not an inert carrier. On one hand, the promoter ion, Co or Ni, can react with the support and occupy octahedral or tetrahedral sites in external layers or even form an inactive phase such as CoAl2O4 (NiAl2O4) depending on the preparation conditions. On the other hand, the molybdates (tunsgtates) interact strongly with the support from the first steps of catalysts preparation through Metal-O-Al anchors. It has suggested that the improvement of HDS catalysts is closely related to the formation of the so-called “NiMoS” (CoMoS, NiWS) phase. Thus, the amount of these phases should be increased by reducing the concentration of inactive species to improve the performance of HDS catalysts. Therefore, the effect of gallium over the CoMo/Al2O3 (CoMo) and NiMo/Al2O3 (NiMo) catalysts was investigated in the HDS of 4,6-dimethyldibenzothiophene. The γ-Al2O3 support was impregnated (before the catalysts were prepared) with an aqueous solution of Ga(NO3)3.8H2O and calcined at 450 ºC. The catalytic results were correlated to the catalysts physicochemical properties which were obtained by different characterization techniques such as X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM) and Diffuse Reflection Spectroscopy (DRS). A change of promoter (Co2+ or Ni2+) interaction with the support is provoked by the affinity of gallium (at low loadings) to the tetrahedral sites of alumina, inducing to an increase of the octahedral species of Ni or Co. This improves the decoration of the MoS2 (WS2) slabs. Gallium also modifies the interaction of MoS2 (WS2) with the support, decreasing the numbers of Metal-O-Al anchors and increasing the MoS2 slabs stacking. These modifications improve the activity of the NiMo, CoMo and NiW catalysts in the deep HDS (4,6-DMDBT HDS)

Extreme silicon thinning for back side power delivery network : Si thinning stopping on scaled SiGe etch stop layer

This paper discusses the challenges relative to the silicon thinning which allows the back side power delivery integration (BSPDN). The back side silicon thinning stopping on a thin Si0.75Ge0.25 etch stop layer (ESL) has been investigated as it represents an alternative to the use of SOI wafers. Etch stop layers using 10 nm Si0.75Ge0.25 or 10 nm Si0.75Ge0.25 boron doped (Si0.75Ge0.25:B) have been studied for which different thinning process sequences were considered. All the considered thinning sequences are terminated with a diluted ammonia (NH4OH) process which provides the selectivity towards the ESL. Considering a 10 nm Si0.75Ge0.25:B as an ESL considerably increases the selectivity of the last diluted NH4OH silicon etching step. It nevertheless induces a risk of device poisoning caused by the diffusion of boron. Considering a 10 nm Si0.75Ge0.25 as an ESL has been then demonstrated using different thinning process sequences. Those alternative thinning sequences were optimized with respect to the silicon removal within wafer uniformity

The Influence of H-2 Plasma Treatment on LWR Mitigation: The Importance of EUV Photoresist Composition

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. To meet the demands for sub-20 nm feature devices in the semiconductor industry, minimizing the line width roughness (LWR) is a critical concern for ultra-large scale integrated circuit manufacturing. Post-lithography treatments should reduce the LWR by at least 50% to meet the technology requirements, but the available post-lithography strategies come short. To support the delayed progress, an in depth understanding of the interaction of such post-lithography treatments with EUV-specific resist functionalities is required. In this article, we analyze the change in line widths and LWR's for 30-35 nm lines using EUV photoresists. In addition we study the effect of the chemical composition on the reduction of LWR after hydrogen plasma treatment using "artificially" prepared reference resists. We highlight the effect of the fluorine unit, ester functionalities and photo acid generator/quencher loading on the LWR improvement and H2 plasma induced reflow.status: publishe

Ar and H2 plasma and neutral/ion beam treatment of EUV resist

status: publishe