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Con este trabajo lo que se pretende es contestar a la pregunta de si realmente es necesario tener un/una instructor/a que nos haga un seguimiento durante las clases simplemente dirigiendo y motivando o si el/la instructor/a debe hacer uso de un aparato tecnológico objetivo que ayude a controlar de mejor manera a sus participantes.

Self assembled monolayers derived from amino silane precursors (C 11 NH 2 ) are studied using conductive AFM (C-AFM) technique in high vacuum (HV) conditions (∼5 × 10 −5 torr). Working in HV condition was preferred to working in air in order to reduce the impact of water meniscus on the surface which increases the adhesion forces causing smearing of the SAMs. C-AFM current maps of these samples indicate a decrease in the number of leakage spots with an increase in the deposition time. The latter is indicative of a trend towards a complete coverage of SAMs for the higher deposition times. To further assess the electrical properties of the SAMs, point I – V spectroscopy measurements were performed up to the point of electrical breakdown. The breakdown voltage increases with the increase in the number of multilayers for the 3 h, 6 h, and 18 h deposition time and then drops for the 24 h deposition time. In this final case we speculate that the numbers of impurity sites are higher and the charge carriers need less electric field to tunnel to the nearest site.

In order to enable an oxide-free Cu-to-Cu bonding in a (dual) damascene process, 3-aminopropyltrimethoxysilane- and decanethiol-derived self-assembled monolayers are selectively deposited in a dielectric-Cu based metal-insulator-metal (MIM) capacitor used as a test vehicle, which represents a dual damascene architecture environment. A two-steps SAM coating sequence is investigated for this purpose. In a first step, a ''sacrificial'' SHSAM is deposited on the Cu areas at the bottom of the vias. In a second step, a ''barrier'' NH"2SAM is deposited on the dielectric areas in the field region and via's sidewalls. This deposition sequence followed by the selective thermal ablation of the ''sacrificial'' SAM vs. the ''barrier'' SAM, enable an oxide-free Cu-to-Cu connection at via's bottom. The differential in thermal stability between the amino and thiol SAMs has been studied by water contact angle and cyclic voltammetry. While the sacrificial SAM is selectively desorbed by thermal ablation already at ~200^oC, the barrier SAM on the dielectric sidewall and field regions withstands a thermal budget as high as ~350^oC. The substrate-selective SAMs depositions are revealed by XPS chemical characterization on the Cu and dielectric areas of the MIM structures supported by the SEM visualization of the Au nanoparticles that selectively decorate the NH"2 functionalities of the barrier SAM.

The traditional Cu interconnect barrier/seed process consisting of PVD-Ta based barrier/Cu-seed will reach its limit between 20 nm and 30 nm wide trench dimension. To extend Cu interconnect technology further, possible solutions such as PVD-RuTa, PEALD-Ru-based, CVD-Co, PVD/CVD-self-formed-MnSixOy and self-assembled monolayers (SAMs) are studied. It is shown that both PVD-RuTa and CVD-Co possess the so-called seed enhancement capability allowing Cu filling of narrow recesses. However, they exhibit limitations in terms of Cu-diffusion barrier efficiency, electromigration reliability and scalability. Despite, the concept of SAM [NH2-SAM(C3)] as Cu diffusion barrier is demonstrated, it requires maturity and compatibility within the process flow (e.g. adhesion with the Cu overlayer). Finally, it is considered that PEALD-Ru-based alloys and CVD-based MnSixOy films are serious candidates for sub-30 nm wide trench technologies because of their conformal nature and ability to act as an efficient Cu diffusion barrier in the range of 2 nm thickness.

A 3-aminopropyltrimethoxysilane-derived self-assembled monolayer (NH 2 SAM) is investigated as a barrier against copper diffusion for application in back-end-of-line (BEOL) technology. The essential characteristics studied include thermal stability to BEOL processing, inhibition of copper diffusion, and adhesion to both the underlying SiO 2 dielectric substrate and the Cu over-layer. Time-of flight secondary ion mass spectrometry and X-ray spectroscopy (XPS) analysis reveal that the copper over-layer closes at 1-2-nm thickness, comparable with the 1.3-nm closure of state-of-the-art Ta/TaN Cu diffusion barriers. That the NH 2 SAM remains intact upon Cu deposition and subsequent annealing is unambiguously revealed by energy-filtered transmission electron microscopy supported by XPS. The SAM forms a well-defined carbon-rich interface with the Cu over-layer and electron energy loss spectroscopy shows no evidence of Cu penetration into the SAM. Interestingly, the adhesion of the Cu/NH 2 SAM/SiO 2 system increases with annealing temperature up to 7.2 J m -2 at 400°C, comparable to Ta/TaN (7.5 J m -2 at room temperature). The corresponding fracture analysis shows that when failure does occur it is located at the Cu/SAM interface. Overall, these results demonstrate that NH 2 SAM is a suitable candidate for subnanometer-scale diffusion barrier application in a selective coating for copper advanced interconnects.

Self-assembled monolayers (SAMs) are investigated as potential Cu diffusion barriers for application in back-end-of-line (BEOL) interconnections. A screening of SAMs derived from molecules with different head group (SiCl"3, Si(OCH"3)"3, Si(OCH"3)Cl"2) bonding to the dielectric substrate, chain lengths (n=3-21) and terminal group (CH"3, Br, CN, NH"2, C"5H"4N and SH) bonding to the Cu overlayer are compared in terms of inhibition of interfacial Cu diffusion and promotion of Cu-SiO"2 adhesion. SAM barrier properties against Cu silicide formation are examined upon annealing from 200 to 400^oC by visual inspection, sheet resistance measurements (Rs) and X-ray Diffraction Spectroscopy (XRD). Cu/SAM/SiO"2 adhesion is evaluated by tape test and four-point probe measurements. Results indicate that NH"2-SAM derived from 3-aminopropyltrimethoxysilane is the most promising for Cu diffusion barrier application. Silicide formation is inhibited to at least 400^oC, essential stability for BEOL integration. However, the 2.9Gc (J/m^2) adhesion of the layer compared with 3.1Gc (J/m^2) on SiO"2 does need improvement.

This study intended to determine the relationship between the level of depression and coping strategies in relatives of victims of forced disappearance in the city of Medellín, Colombia. The research involved 34 grown-up participants, of both genders (4 men and 30 women) ages between 18 and 71, who were relatives of victims of forced disappearance at 6-21 months from the event occurrence. They completed Beck depression inventory, validated and standardized for Mexican population (Jurado, 1998) as well as the Coping Styles Questionnaire (Sandin & Chorot, 2003). General population means were compared in terms of age groups, relative's disappearance time and the participants' previous attendance to psychotherapy. 79.4% of participants had relatives who had disappeared 6-12 months before, and 58.8% of participants had not received psychological support. Depression levels were in a minimum/free-of-symptom level in 29.4% of population, in 23.5% they were slight, in 41.2% they were moderate and they showed to be severe in 5.9% of participants. The relationship between depression and coping styles levels was not statistically significant, yet focusing on problem solving and religion appeared as protection factors against depression Se buscó determinar la relación entre el nivel de depresión y las estrategias de afrontamiento en familiares de personas víctimas de desaparición forzada de la ciudad de Medellín, Colombia. Los participantes fueron 34 personas adultas de ambos géneros (4 hombres y 30 mujeres) con un rango de edad 18 a 71 años de edad, familiares de víctimas de desaparición forzada de entre 6 y 21 meses de haber acontecido el evento, a quienes se les aplicó el cuestionario de depresión de Beck validado y estandarización en población mexicana (Jurado, 1998) y el cuestionario de estilos de afrontamiento (Sandin & Chorot, 2003). Se hicieron comparaciones con los promedios de la población general de acuerdo con los grupos de edad, tiempo de desaparición del familiar y asistencia previa a psicoterapia de los participantes. El 79,4% presentaban familiares desaparecidos entre 6 y 12 meses y el 58,8% no había recibido apoyo psicológico. Los niveles de depresión de la población se presentaron en 29,4% mínimo o sin síntomas, 23,5% leve, 41,2% moderada y 5,9% severa; aunque la relación entre el nivel de depresión y los estilos de afrontamiento no es estadísticamente significativa, la focalización en la solución de problemas y la religión parecen factores protectores del nivel de depresión.

The RC delay and power restrictions imposed by the interconnect system can contribute to poor circuit performance in an increasingly severe manner as dimensions shrink. Resistances are increasing faster than the scale factor of the technology and capacitance improvements are constrained by mechanical requirements of the assembled stack. Collectively, these cause a bottleneck in both local and global information transfer on a chip. Novel deposition methods and novel conductor materials are being explored as means to increase conductive cross sectional area. Molecular ordering is an opportunity to simultaneously deliver capacitance and mechanical strength. Despite these improvement paths, a more holistic approach to interconnect design is needed, where the application and micro architecture are more tolerant of RC scaling constraints.

This work presents the first fabricated and characterized MEMS in polycrystalline silicon-germanium (poly-SiGe) for biosensing applications. The devices, clamped-clamped microresonators, combine the possibility of above-IC MEMS-CMOS integration with a stiction-free design that enables biomolecule mass sensing in air. By perforating the resonant beam with square or hexagonal holes, a higher surface-to-volume ratio is achieved leading to an increased relative frequency shift for a certain analyte surface density. A minimum detectable mass of ∼2pg in air was calculated. A mass sensing test was performed on these perforated devices by immobilization of biotin and the extraction of the resulting resonance frequency shift.

Two different material-selective Self assembled monolayers (SAMs) were successfully deposited on Cu and SiO 2 structures that mimic the Dual Damascene integration scheme. A two-step SAM coating process is presented. First, a “sacrificial” SAM is deposited at the Cu bottom and secondly, a “barrier” SAM at the SiO 2 surface. The order in the SAMs deposition sequence and the differential thermal release of the thiol “sacrificial” SAM vs. the amino “barrier” SAM, allows an oxide-free Cu-to-Cu connection at the vias bottom. While the sacrificial SAM is selectively released by thermal ablation, the barrier SAM remains intact on the dielectric sidewall and field regions, ready for the subsequent copper metallization.

The trend for future integrated circuits (IC) is decreasing in size beyond the conventional limits. The recent transition from aluminum to copper as the interconnect material for IC is due to copper's higher resistance to electromigration and its lower resistivity. Unfortunately, copper has high mobility in Si and SiO2 and may cause destruction of electrical connections on the chip. Hence, there is a significant necessity in finding ultra thin, thermally stable, high quality and good adhered diffusion barriers. The most widely used barrier is pure Ta films or layer stacks consisting of Ta and TaN. These have excellent conformality, very good uniformity and high thermal stability. But The continuous scaling down of the interconnect dimensions lead to an essential decrease in the barrier layer effective thickness to less than 5nm; coupled with the replacement of silicon oxide by advanced low-k dielectrics it demand further improvements of the diffusion barrier performance. For that reason Self-assembled monolayers (SAMs), with thicknesses of 2nm or less, have been propose for copper diffusion barrier application. By tailoring the structure of these monomolecular organic films, atomic scale properties can be controlled and selective surfaces and interfaces can be engine as desired for a specific application. In the presented work, the quality of an amino-terminated SAM barrier (NH2SAM) is tested. A high density and the absence of pinholes in the barrier layer are essential for a good barrier performance. First, the macroscopic quality of the NH2SAM barrier has been characterized by Water contact angle (CA) and High resolution AFM (HR-AFM). Secondly, the density and the presence and/or absence of pinholes have been tested by Ellipsometry and Cylic Voltametry (CV). Finally, the intrinsic barrier performance in form of Time- dependent dielectric breakdown (TDDB) lifetime has been extracted from planar capacitor structures that permitted to measure the leakage/Cu diffusion through barrier in the vertical direction. The Contact angle of layers formed at different deposition times show a variation of the hydrophilic SiO2 substrate to hydrophobic already with 1min deposited NH2SAM layer. A 15min deposited NH2SAM (~1nm), results in a continuous and pinhole free layer observed by HR-AFM. The refraction index (η) calculated by ellipsometry, indicates an increase in the density of the layer with the deposition time. On the other hand, cyclic voltametry shows inhibition of the electrochemical reduction of Fe3+ specimen to Fe2+ when NH2SAM are formed on ~2nmSiO2/Si electrodes. A decrease in the capacitive current is observed by increasing the layer thickness and density. The intrinsic barrier performance of the NH2SAM barrier by TDDB is demonstrated with an increase of 10 times the capacitor lifetime by comparing with no barrier system.

This paper investigates a selective self-assembly process for formation of a self-assembled monolayers (SAM) barrier to Cu diffusion in dual damascene integration. In selecting a barrier, trichlorosilanes are promising due to their high thermal stability (above 550degC) and dense molecular packing. Overall, this study demonstrates that the tuneable structure and chemistry of SAMs provides a molecular level engineering approach for future device structures.

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An alternative bottom-up Cu electroless deposition (ELD) method without other catalyst material activation is the focus of this paper. The process consists of reducing the Cu ions in a solution via standard reducing agents such as dimethylamine borane. The reaction pH and ionic strength values can be modulated to impart to the metallic Cu particle surface an opposite charge with respect to the deposition substrate functionalized by the 3-aminopropyltrimethoxysilane (APTS) self-assembled monolayer used as a diffusion barrier. At neutral pH, the negatively charged Cu particles are electrostatically attracted by the positively charged NH 2 groups, and they can form strong interfacial complexes if the required activation energy budget is supplied. A design of the experiment is carried out to optimize the critical deposition parameters such as temperature, time, Cu ion concentration, and pH. The formed ELD Cu nuclei positioned preferentially on the APTS layer, showing a wetting behavior that is accentuated upon anneal, leading to a decrease in surface roughness that corresponds to an increase in film closure. The observed debonding energy of the ELD Cu/APTS surface is ca. 2.2 J/m 2 before anneal, while it reaches ca. 4.5 and 8 J/m 2 after a 10 min anneal under forming gas at 300 and 450°C, respectively.