A Comparison of TSV Etch Metrology Techniques

International audienceWe use three metrology techniques, vertical scanning interferometry (VSI), confocal chromatic microscopy (CCM), and time domain optical coherence tomography (TD-OCT), for depth measurement of through-silicon vias (TSVs) of various cross sections and depths. The merits of these techniques are discussed and compared. Introduction While sales of semiconductor equipment broke a new record this year, many metrology needs should be addressed to support the development and production of electronic chips based on "More than Moore" scaling. Among these scaling approaches, 3D integration based on TSVs offers superior integration density and reduces interconnect length/latency. Measurements are needed to evaluate the depth uniformity of etched TSVs. Indeed, upon metal filling, geometrical variations of TSVs can affect Cu nails coplanarity and can warp the wafer, resulting in a low stacking yield. Measuring the depth of TSVs is an increasingly challenging task as the diameter of many TSVs has now shrunk to only a few microns

Évangélisateurs et évangélisés, exemple d'un contact. La fondation d'une mission chez les Gallas en Éthiopie par les Capucins (1846-1936)

In parallel with the evangelization of the animist tribes of West Africa in the XIXth century, the Capuchin missionaries chose to bring religion and Christian virtues to East Africa. The Capuchin missions to Ethiopia began in 1846 and it was in 1883 that the Capuchin province of Toulouse was granted the Vicariate Apostolic of Gallas. Penetration of Gallas was long and dangerous, as much due to the hostile nature of the land as to the religious environment (Copts and Muslims) but also due to multiple political coveting. The missionary brimming with apostolic zeal labours, in principle, to defeat all that he considers to be barbarity. The process of "humanization" and "civilization" went from the education of young girls to teaching in schools to nursing care given in free clinics, to the freeing of the slaves, etc. In 1936, with the Italian colonization of Ethiopia, the Toulouse Capuchins had to leave way to the Italian Capuchins.Parallèlement à l'évangélisation au XIXe siècle des tribus animistes de l'Ouest de l'Afrique, les missionnaires capucins ont, eux, choisi de porter la religion et les vertus chrétiennes à l'Est de l'Afrique. Les missions capucines vers l'Éthiopie ont débuté en 1846 et c'est en 1883 que la province capucine de Toulouse se voit attribuer le Vicariat Apostolique des Gallas. La pénétration en pays galla a été longue et périlleuse, tant par la nature hostile du pays que par l'environnement religieux (coptes et musulmans) mais aussi par les convoitises politiques multiples. Le missionnaire, plein de zèle apostolique, œuvre en principe à rejeter tout ce qu'il considère comme étant de la barbarie. Ce travail d'« humanisation » et de « civilisation » passe ainsi par l'éducation des jeunes filles, l'enseignement dans les écoles, les soins infirmiers donnés dans les dispensaires, la libération des esclaves, etc. En 1936, du fait de la colonisation italienne de l'Éthiopie, les Capucins Toulousains devront laisser la place aux Capucins Italiens

Mitochondrial DNA spectra of single human CD34+ cells, T cells, B cells, and granulocytes

Previously, we described the age-dependent accumulation of mitochondrial DNA (mtDNA) mutations, leading to a high degree of mtDNA heterogeneity among normal marrow and blood CD34+ clones and in granulocytes. We established a method for sequence analysis of single cells. We show marked, distinct mtDNA heterogeneity from corresponding aggregate sequences in isolated cells of 5 healthy adult donors—37.9% ± 3.6% heterogeneity in circulating CD34+ cells, 36.4% ± 14.1% in T cells, 36.0% ± 10.7% in B cells, and 47.7% ± 7.4% in granulocytes. Most heterogeneity was caused by poly-C tract variability; however, base substitutions were also prevalent, as follows: 14.7% ± 5.7% in CD34+ cells, 15.2% ± 9.0% in T cells, 15.4% ± 6.7% in B cells, and 32.3% ± 2.4% in granulocytes. Many poly-C tract length differences and specific point mutations seen in these same donors but assayed 2 years earlier were still present in the new CD34+ samples. Additionally, specific poly-C tract differences and point mutations were frequently shared among cells of the lymphoid and myeloid lineages. Secular stability and lineage sharing of mtDNA sequence variability suggest that mutations arise in the lymphohematopoietic stem cell compartment and that these changes may be used as a natural genetic marker to estimate the number of active stem cells

Regulation of the cell-cycle-dependent internal ribosome entry site of the PITSLRE protein kinase: roles of Unr (upstream of N-ras) protein and phosphorylated translation initiation factor eIF-2α

The PITSLRE kinases belong to the large family of cyclin-dependent protein kinases. Their function has been related to cell-cycle regulation, splicing and apoptosis. We have previously shown that the open reading frame of the p110(PITSLRE) transcript contains an IRES (internal ribosome entry site) that allows the expression of a smaller p58(PITSLRE) isoform during the G(2)/M stage of the cell cycle. In the present study we investigated further the role of cis- and trans-acting factors in the regulation of the PITSLRE IRES. Progressive deletion analysis showed that both a purine-rich sequence and a Unr (upstream of N-ras) consensus binding site are essential for PITSLRE IRES activity. In line with these observations, we demonstrate that the PITSLRE IRES interacts with the Unr protein, which is more prominently expressed at the G(2)/M stage of the cell cycle. We also show that phosphorylation of the α-subunit of the canonical initiation factor eIF-2 is increased at G(2)/M. Interestingly, phosphorylation of eIF-2α has a permissive effect on the efficiency of both the PITSLRE IRES and the ornithine decarboxylase IRES, two cell cycle-dependent IRESs, in mediating internal initiation of translation, whereas this was not observed with the viral EMCV (encephalomyocarditis virus) and HRV (human rhinovirus) IRESs