Microchips are more and more complex and designed in thick 3-dimensional packages. Direct observation of the inside of the device by electron microscopy in order to check the manufacturing quality or to analyse the origin of failures requires the removal of huge quantity of matter. The current techniques, such as plasma Focused Ion beam, provide high surface quality but at the cost of a low matter removal rate (~10 4 μm 3 /s), requiring hours of processing. This problem becomes worse for the realisation of TEM lamella for which double cavities must be engraved. Therefore, other techniques such as laser engraving are envisioned in order to accelerate the process (Halbwax et al. 2007, Kwakman et al. 2013, Sikora et al. 2016). In this work, picosecond laser micromachining at 343, 515 and 1030 nm was investigated for the realization of cross sections and lamella. By working at a modest repetition rate (200 kHz), much higher matter removal rates could be achieved (~10 6 μm 3 /s) reducing the cavity engraving time to several seconds (Sikora et al. 2016). Besides, smooth and almost vertical sidewalls were obtained by tuning the applied fluence and the number of shots. The method is demonstrated for cross sectioning of highly heterogeneous devices such as microchips and for the realization of thin lamella in silicon.

Microchips are more and more complex and designed in thick 3 dimensional packages. In order to access and characterize by electron microscopy (SEM and TEM) any detected defect responsible for malfunction of the device, a large quantity of matter needs to be removed without damaging the surrounded area. The available techniques, such as plasma Focused Ion Beam (FIB), allow achieving high quality surfaces but are limited by their low matter removal rate (∼10 4 μm 3 /s). In order to accelerate the process, other techniques such as laser micromachining of the sample prior to FIB polishing are envisioned [1, 2]. In this work, picosecond laser micromachining has been investigated at 3 wavelengths (343, 515 and 1030 nm) in silicon and tested in integrated circuits. In order to minimize the FIB polishing time, the laser induced damaged zone should be the least extended and the micromachined sidewalls should be as vertical and smooth as possible. It is shown that by using sufficiently high fluences and number of pulses, almost vertical and smooth sidewalls can be obtained (see Fig. la) [3]. Moreover, according to the TEM images, sidewalls are only covered by a few hundred nm thick debris layer with limited heat affected zones. These results, coupled with the high matter removal rate (∼10 6 μm 3 /s) demonstrate that picosecond laser machining fulfills the requirements for sample preparation. The processing method was successfully tested on microchips as shown by SEM imaging which reveals clean exposed interfaces of underlayers (see Fig. 1b). In addition, using a simple model allowing a better understanding of laser absorption in silicon for picosecond pulses, the conditions (wavelength and fluence) to achieve optimal matter removal rate and ablation efficiency were identified and validated by experimental results.

Non-Volatile Memories (NVM) integrating silicon nanodots (noted SDs) are considered as an emerging solution to extend Flash memories downscaling. In this alternative memory technology, silicon nanocrystals act as discrete traps for injected charges. Si-dots were grown by Low Pressure Chemical Vapor Deposition (LPCVD) on top of tunnel oxide. Depending on the pre-growth surface treatment, tunnel oxide surface may present either siloxane or silanol groups. SDs deposition relies on a 2–steps process: nucleation by SiH4 and selective growth with SiH2Cl2. In a context of technological industrialization, it is of primary importance to develop in-line metrology tools dedicated to Si-dots growth process control. Hence, silicon-dots were observed in top view by using an in-line Critical Dimension Scanning Electron Microscopy CDSEM and their average size and density were extracted from image processing. In addition, Haze measurement, generally used for bare silicon surface characterization, was customized to quantify Si-dots deposition uniformity over the wafer. Finally, Haze value was correlated to Si nanodots density and size determined by CDSEM.

The aim of this paper is to check the effect of artefacts introduced by focused ion beam (FIB) milling on the strain measurement by convergent beam electron diffraction (CBED). We show that on optimized silicon FIB samples, the strain measurement can be performed with a sensitivity of about 2.5 x 10(-4) which is very close to the theoretical one and we conclude that FIB preparation can be suitable for such measurements in microelectronic devices. To achieve this, we first used CBED and electron energy loss spectroscopy (EELS) which provide a procedure permitting an exact knowledge of the sample geometry, i.e. the thickness of both amorphous and crystalline layers. This procedure was used in order to measure the FIB-amorphized sidewall layer. It was found that if the FIB preparation is optimized one can reduce this amorphous layer down to around 7 nm on each side. Secondly different preparation techniques (cleavage, Tripodtrade mark and FIB) permit to check if the surface damaged layer introduced by FIB influences the strain state of the sample. Finally, it was found that the damaged layer does not introduce measurable strain in pure silicon but reduces appreciably the quality of the CBED patterns.

The latest International Technology Roadmap for Semiconductors (ITRS) has highlighted the detection and analysis of defects in Integrated Circuits (IC) as a major challenge faced by the semiconductor industry. Advanced tools used today for defect cross sectioning include dual beams (focused ion- and electron-beam technologies) with resolution down to the sub-Angstrom level. However ion milling an IC with a FIB is time consuming because of the need to open wide cavities in front of the cross-sections that need to be analyzed. Therefore the use of a femtosecond laser as a tool for direct material removal is discussed in this paper. Experiments were performed on IC structures to reveal the different layers of fabrication: selective or total ablation can occur depending on the laser energy density, without delamination of the layers. Different laser irradiation conditions like pressure (air, vacuum), polarization, beam shaping, and scanning parameters have been used to produce different types of cavities. The femtosecond laser engraving of silicon-based structures could be useful for cross-sectioning devices but also for other applications like direct-write lithography, photomask repair, maskless implantation or reverse engineering/restructuring. (C) 2007 Published by Elsevier B.V.

The objective of this work is to determine the origin of a decohesion problem that occurs during the fabrication process of certain integrated circuits. This decohesion takes place at the Ti/dielectric interface with the dielectric being either SiO 2 or borophosphosilicate glass (BPSG). The frequency of the decohesion increased when the dielectric is BPSG. In order to understand the reason for the difference in decohesion rates for the two dielectrics, a comparative study was performed before and after annealing. X-ray Diffraction was used to determine the microstructure of the different layers and Transmission Electron Microscopy coupled to Electron Energy Loss Spectroscopy and X-ray Energy Dispersive Spectroscopy was mainly used to characterize the interfaces and nanophases that had formed during annealing. A fundamental difference observed was the Ti/dielectric interface reactivity: in the case of BPSG, an amorphous layer rich in P is formed before the Ti 5 Si 3 silicide. Two hypothesis are put forward in order to explain adhesion failures: a decrease in the rate of Ti 5 Si 3 formation kinetics and/or a decrease of the glass transition temperature induced by P enrichment.

The formation of Ti silicides has been examined in flash memories with 0.25 μm linewidth by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. It has been observed that, after the first rapid thermal process and the selective metal etch, there is no silicide on the source and on a majority of drain contacts while C49-TiSi2 is found on the gate. A pre-amorphisation implant increases drastically the formation of C49-TiSi2 in the drain zone while modifications of annealing conditions have little impact. These results indicate that the formation of C49-TiSi2 is most likely controlled by nucleation and that this nucleation is sensitive to both the width and the length of the reaction zone. The formation of a Ti rich silicide may play an important role in this nucleation by decreasing the driving force for the formation of C49-TiSi2. Curiously enough, the formation of C49-TiSi2 appears thus as a major concern for the salicide process in flash memories.

In the present study, structural modifications induced by eauilibrium sulphur segregation in pure tilt germanium {710}<001>, ∑=25 (θ=16.26°) and {551}<011>, ∑=51 (θ=16.10°) grain boundaries (GBs) were investigated using high-resolution electron microscopy coupled to electron-energy-loss spectroscopy and supported by structural modelling and image simulations. Our results showed that the as-grown ∑=25 GB is composed of two parts: a stable structural region and a variable perturbed core. On the basis of our simulations, it is shown that this boundary can only be formed by a multiplicity of configurations which are energetically close to each other but differently configured along the boundary plane. When sulphurized, drastic changes in the structure of the GB were observed. Energy-filtered electron microscopy imaging revealed a sulphur enrichment at the perturbed part of the boundary. Although sulphur segregation at the boundary is detected, no information can at the present stage be extracted on segregation sites and bonding configurations because of the complexity of the boundary structure. To simplify this aspect, a simpler GB, that is germanium ∑=51, was studied. The structure of such a GB is a well-known configuration, that is a Lomer dislocation, which is basically a fivefold ring adjacent to a sevenfold ring. After sulphur treatment, high-resolution electron microscopy imaging also shows significant contrast modifications apparently concentrated on the dislocation core. Chemical imaging indicates again the presence of sulphur enrichment along the boundary plane strongly sustaining that eauilibrium sulphur segregation in the Ge(S) system oceurs into the GB and therefore confirms our previous results on the ∑= 25 GB. One can therefore argue that it is the presence of those odd-membered rings at the boundary, which should possess a specific crystallographic and electronic nature, coupled to the electronic properties of sulphur, that are responsible for the preferential segregation into the boundary.

In this article, evidence will be put forward for the first time about modifications of the Si (100) surface induced by standard SC1/SC2 etching cycles. SC1/SC2 etching (also known as RCA cleaning) submits silicon wafers to oxidation by NH3:H2O2:H2O mixtures, oxide removal in diluted HF, further oxidation by HCl:H2O2:H2O mixtures, and final etching in diluted HF. Samples were analysed using high-resolution transmission electron microscopy (HRTEM)-parallel electron energy loss spectroscopy (PEELS) and Low-energy electron diffraction (LEED) techniques. HRTEM-PEELS analyses were carried out adopting a special cross-section geometry enhancing HRTEM sensitivity to surface species. Atomic-resolution HRTEM micrographs displayed a partial loss of the crystalline order in a 4 nm layer at the Si surface only when samples had undergone SC1/SC2 cycles. No (2×1) reconstruction pattern could be observed by either HRTEM or LEED. PEELS analyses allowed one to rule out the presence of either oxygen, carbon or fluorine at the surface or within the disordered layer, thereby leading to the conclusion that oxidation treatments yield to a modification of the crystalline structure at the Si (100) surface.

An original experimental procedure is set up in order to relate unambiguously the equilibrium impurity segregation in a grain boundary to the structural modifications. This is clearly established in the case of the Ge(S) Σ=25 grain boundary. Using HREN, EDS and EELS, we show that the sulfur segregation occurs on the dislocation cores of the grain boundary and that it stabilizes the lowest energy structures of the initial one.

Infections in systemic lupus erythematosus are frequent. However, osteoarticular Salmonella infections are rarely reported. We report a case of systemic lupus erythematosus diagnosed in a 15 year-old girl. Seven months later, she presented with fever and a localized collection of the upper extremity of the left tibia related to a Salmonella enteritidis acute osteomyelitis (sub periosteal abscess). The out-come was chronic and led to death. The authors emphasize the severity of non typhoidal salmonellosis in systemic lupus erythematosus.

Les infections au cours du lupus érythémateux disséminé sont fréquentes mais les infections ostéoarticulaires à salmonelles sont rarement relatées dans la littérature. Nous rapportons l'observation d'une patiente de 15 ans chez laquelle le diagnostic de lupus érythémateux disséminé a été retenu. Sept mois plus tard, elle présente une fièvre avec une collection fluctuante au niveau de l'extrémité supérieure du tibia gauche. Le diagnostic d'ostéomyélite épiphysaire du tibia au stade d'abcès sous-périoste à Salmonella enteritidis est retenu. L'évolution s'est faite vers la chronicité puis vers le décès. Les auteurs insistent sur la gravité des salmonelloses non typhiques chez les lupiques.

A retrospective study of 404 cases of rheumatoid arthritis seen in a department of internal medicine in Casablanca highlights a number of specific features of the disease in Morocco. Onset occurred early and mean age of patients was 34.4 years. Analysis of joint manifestations showed that the disease tended to be mild in the hips and perhaps in the cervical spine. Thirty-five percent of patients were Steinbrocker's class II and 25.5% had carpal bone fusion. Only 20 patients had severely erosive disease, which manifested as giant geodes in 8 cases and as main en lorgnette deformity in one case. Subcutaneous nodules (7.9%) and systemic visceral disorders were fairly infrequent. Only three cases of malignant rheumatoid arthritis were found. Gougerot-Sjögren syndrome was present in 13.6% of patients. Among comorbid conditions, thyroid gland diseases and tuberculosis were fairly common. Serologic tests were positive in 61.14% of cases, often in low titres. Gold salt therapy was well tolerated. No patients in this group had surgical treatment. These data suggest that in Morocco rheumatoid arthritis may be less aggressive than in Europe.

A retrospective study of 404 cases of rheumatoid arthritis seen in a department of internal medicine in Casablanca highlights a number of specific features of the disease in Morocco. Onset occurred early and mean age of patients was 34.4 years. Analysis of joint manifestations showed that the disease tended to be mild in the hips and perhaps in the cervical spine. Thirty-five percent of patients were Steinbrocker's class II and 25.5 % had carpal bone fusion. Only 20 patients had severely erosive disease, which manifested as giant geodes in 8 cases and as main en lorgnette deformity in one case. Subcutaneous nodules (7.9 %) and systemic visceral disorders were fairly infrequent. Only three cases of malignant rheumatoid arthritis were found. Gougerot-Sjogren syndrome was present in 13.6 % of patients. Among comorbid conditions, thyroid gland diseases and tuberculosis were fairly common. Serologic tests were positive in 61.14 % of cases, often in low titres. Gold salt therapy was well tolerated. No patients in this group had surgical treatment. These data suggest that in Morocco rheumatoid arthritis may be less aggressive than in Europe.

This study rest on 404 Rheumatoid Arthritis (R.A.) case reports in Moroccan circle. R.A. occurs in an earlier age. Its agressiveness would be lesser because of : discretion of suffering from coccy-femoral arthritis, rarity of highly erosive forms, lesser rate of subcutaneous nodes, and fairly large toleration of gold drugs.

This study rest on 404 Rheumatoid Arthritis (R.A.) case reports in Moroccan circle. R.A. occurs in an earlier age. Its agressiveness would be lesser because of: discretion of suffering from coccy-femoral arthritis, rarity of highly erosive forms, lesser rate of subcutaneous nodes, and fairly large toleration of gold drugs.