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As reverse transcription is predominantly performed by retrotransposable elements, the process is often entirely associated with the propagation of these elements. However, as a unique tool for transmitting information from the dynamic RNA to the more inert DNA, reverse transcription has been instrumental in shaping extant genomes. This review aims at presenting the diversity by which reverse transcription has influenced modern genomic structures. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

With the integration of copper as a conductive material in interconnects, post-electroplating anneal plays a key role in controlling the copper characteristics. Meanwhile, there is a constant need to reduce the thermal budget in the back-end processes. In this context, short on-board anneals are an interesting alternative to long batch furnace thermal treatments. In this work, we evaluate the impact of such short anneals on copper properties. Microstructural, mechanical and contamination results show that short on-board anneals at 400 °C offer performances that are similar to longer furnace anneals at the same temperature, whereas 250 °C anneals are clearly insufficient. Integration issues such as copper adhesion are investigated. [Copyright &y& Elsevier]

Abstract: Future generations of integrated circuits will require interconnects with metallic lines at dimensions below 50nm. When Cu is used, the electron mean free path becomes similar to the characteristic dimensions of the structure of the metallic line (grain size, interface and wall spacing). This induces a large metal resistivity increase which has a negative impact on the circuit performance. Cu resistivity models have been proposed using the classical Fuchs and Sondheimer approach for surface effect, and the Mayadas and Shatzkes approach for the grain boundary effect (FS–MS approach). In these models, three adjustable parameters must be used. Good agreement between experimental resistivity vs linewidth curves and models can easily be obtained. However, numerous fitting parameter sets can be obtained with equivalent fitting quality and opposite physical meaning. In this work, experiments dedicated to model parameter extraction are proposed and released. They are based on the used of Cu lines with various line widths and heights. Special care is taken in the accuracy of resistivity and dimensions measurements. Classical resistivity increase with line width and line height decrease is observed. Using the FS–MS approach, the observed resistivity behaviour is modelled. In this case, limited fitting parameter options are obtained. For Cu narrow lines confined with Ta, these parameters suggest high surface effect, medium grain boundary effect and low impurity content inside the lines. [Copyright &y& Elsevier]

Abstract: An alternative, and quicker way of assessing the electromigration (EM) reliability of Cu interconnects is investigated. It is based on observations of de-wetting and contact angle measurement of Cu thin films. Contact angle results are compared to EM tests, and the correlation between Cu de-wetting and electromigration performance is demonstrated. PVD TaN x /Ta or ALD TaN barrier layers are tested, while the seed layer is either pure copper or a CuAl1 at%. In addition, three types of barrier treatments are investigated: different exposure times to plasma of ALD TaN; tantalum flash between ALD TaN and pure copper seed deposition; ALD TaN exposure to atmospheric oxygen. [Copyright &y& Elsevier]

Sample preparation for high-throughput sequencing (HTS) includes treatment with various laboratory components, potentially carrying viral nucleic acids, the extent of which has not been thoroughly investigated. Our aim was to systematically examine a diverse repertoire of laboratory components used to prepare samples for HTS in order to identify contaminating viral sequences. A total of 322 samples of mainly human origin were analysed using eight protocols, applying a wide variety of laboratory components. Several samples (60% of human specimens) were processed using different protocols. In total, 712 sequencing libraries were investigated for viral sequence contamination. Among sequences showing similarity to viruses, 493 were significantly associated with the use of laboratory components. Each of these viral sequences had sporadic appearance, only being identified in a subset of the samples treated with the linked laboratory component, and some were not identified in the non-template control samples. Remarkably, more than 65% of all viral sequences identified were within viral clusters linked to the use of laboratory components. We show that high prevalence of contaminating viral sequences can be expected in HTS-based virome data and provide an extensive list of novel contaminating viral sequences that can be used for evaluation of viral findings in future virome and metagenome studies. Moreover, we show that detection can be problematic due to stochastic appearance and limited non-template controls. Although the exact origin of these viral sequences requires further research, our results support laboratory-component-linked viral sequence contamination of both biological and synthetic origin. Image 1 [ABSTRACT FROM AUTHOR]

Highlights • Copper pillars are imaged using 6 different 3D imaging techniques. • 3rd generation synchrotron beamlines and lab equipments are assessed. • A new sample preparation for synchrotron tomography is successfully tested. • The final volumes are compared, based on image quality and analysis time. Abstract In microelectronics, recently developed 3D integration offers the possibility to stack the dice or wafers vertically instead of putting their different parts next to one another, in order to save space. As this method becomes of greater interest, the need for 3D imaging techniques becomes higher. We here report a study about different 3D characterization techniques applied to copper pillars, which are used to stack different dice together. Destructive techniques such as FIB/SEM, FIB/FIB, and PFIB/PFIB slice and view protocols have been assessed, as well as non-destructive ones, such as laboratory-based and synchrotron-based computed tomographies. A comparison of those techniques in the specific case of copper pillars is given, taking into account the constraints linked to the microelectronics industry, mainly concerning resolution and sample throughput. Laboratory-based imaging techniques are shown to be relevant in the case of punctual analyses, while synchrotron based tomographies offer highly resolved volumes for larger batches of samples. [ABSTRACT FROM AUTHOR]

In this study, SiOCH thin films were deposited by filament assisted chemical vapor deposition using methyltriethoxysilane. It is shown that annealing the films at 400 °C (with or without UV-assist) is required to meet specifications in terms of dielectric properties (low-κ values and good insulating properties). This work highlights FACVD as a promising technique to allow the deposition of conformal dielectric thin films within High-Aspect-Ratio TSVs. Step coverage higher than 70% were obtained within 10 ∗ 80 μm TSVs. Then, FACVD deposited SiOCH films can be considered as a promising candidate for use within TSV technologies. [ABSTRACT FROM AUTHOR]

Plasmodium knowlesi is an intracellular malaria parasite whose natural vertebrate host is Macaca fascicularis (the ‘kra’ monkey); however, it is now increasingly recognized as a significant cause of human malaria, particularly in southeast Asia. Plasmodium knowlesi was the first malaria parasite species in which antigenic variation was demonstrated, and it has a close phylogenetic relationship to Plasmodium vivax, the second most important species of human malaria parasite (reviewed in ref. 4). Despite their relatedness, there are important phenotypic differences between them, such as host blood cell preference, absence of a dormant liver stage or ‘hypnozoite’ in P. knowlesi, and length of the asexual cycle (reviewed in ref. 4). Here we present an analysis of the P. knowlesi (H strain, Pk1(A+) clone) nuclear genome sequence. This is the first monkey malaria parasite genome to be described, and it provides an opportunity for comparison with the recently completed P. vivax genome and other sequenced Plasmodium genomes. In contrast to other Plasmodium genomes, putative variant antigen families are dispersed throughout the genome and are associated with intrachromosomal telomere repeats. One of these families, the KIRs, contains sequences that collectively match over one-half of the host CD99 extracellular domain, which may represent an unusual form of molecular mimicry. [ABSTRACT FROM AUTHOR]

As the sharpness of the metal–oxide interface is of major importance to develop efficient structures, we have studied the thermal stability of interfaces in a series of thin film samples where the metallic component was either Pt, Al, Pd, Ni, Nb or Ti deposited on a thin HfO2 film. Thermodynamic considerations have been carried out to determine the possible products of metal–oxide reaction at a temperature of 500 °C. The evolution of the as-deposited thin film structures as a function of annealing temperature has been analysed by combining various techniques and specifically using X-ray reflectometry. This particular technique allows one to detect very thin embedded interfaces, distinguish small density variations and determine accurately the thickness, the normal roughness and the density of each layer. In addition, reflectometry results have been correlated with atomic force microscopy and transmission electron microscopy observations of selected samples. Our results indicate that platinum, palladium and nickel are stable up to 500 °C on hafnium oxide. Annealed aluminium, an interfacial layer forms, whereas niobium and titanium present a diffuse interface. [Copyright &y& Elsevier]

Copper deposition using (hfac)Cu(MHY) (Gigacopper®) for interconnections metallization by Cu CVD is presented. We compared it to (hfac)Cu(VTMS) (Cupraselect®) in terms of deposition rate, specific resistivity and uniformity. Gigacopper® appears to give a higher deposition rate than Cupraselect® and about the same specific resistivity. Water addition is a critical point. It permits improved uniformity and specific resistivity provided it is added during the nucleation step in a very precise volume. We also studied the influence of other parameters, such as precursor flow rate and reactor pressure, on the film deposition. The use of Cu CVD as seed layer for Cu ECD depositions was also explored on full sheet wafers. Adhesion can be greatly enhanced by a specific anneal procedure with a slow cool down to limit stresses in the film. [Copyright &y& Elsevier]