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Three-dimensional hybrid bonding integration challenges and solutions toward multi-wafer stacking
- L. Arnaud, C. Karam, N. Bresson, C. Dubarry, S. Borel, M. Assous, G. Mauguen, F. Fournel, M. Gottardi, T. Mourier, S. Cheramy, F. Servant
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- Journal:
- MRS Communications / Volume 10 / Issue 4 / December 2020
- Published online by Cambridge University Press:
- 07 October 2020, pp. 549-557
- Print publication:
- December 2020
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Recent applications require vertical chip stacking to increase the performance of many devices without the need of advanced node components. Image sensors and vision systems will embed more and more smart functions, for instance, image processing, object recognition, and movement detection. In this perspective, the combination of Cu-to-Cu direct hybrid bonding technology with Through-Silicon-Via (TSV) will allow 3D interconnection between pixels and the associated computing and memory structures, each function fabricated on a separate wafer. Wafer-to-wafer hybrid bonding was achieved with multi-pitch design—1–4 μm—of single levels of Cu damascene patterned on 300 mm silicon substrates. Defect-free bonding, as far as the extreme edge of the wafer, was demonstrated on a stack with three wafers. Middle wafers thinning was done with grinding only and with a thickness uniformity (TTV) <2 μm to an ultimate thinning as low as 3 μm. Alignment performance was characterized by post-bonding for two superposed hybrid bonding interfaces. In our set of wafers, modeling the alignment with translation, rotation, and scaling components enables us to optimize the residuals down to 3σ < 100 nm. A process flow of thin TSV with a fine pitch of 2 μm for high-density vertical interconnect through a three-wafer stack was developed. Via-last TSV architecture was adopted with 1 μm TSV diameter and 10 μm thickness. Lithography, etching solutions, Ti/TiN barrier deposition, and void-free Cu filling solutions were demonstrated. TSV cross sections after CMP and connections with top and bottom Cu damascene lines show good profile control. Process developments are matured and can be reliably used in the fabrication of an electrical test vehicle including vertical interconnects associating multi-wafers stacking with a hybrid bonding process and high-density thin TSV applicable to low pitches (<5 μm).
Quality and safety of bovine clones and their products
- Y. Heyman, P. Chavatte-Palmer, G. Fromentin, V. Berthelot, C. Jurie, P. Bas, M. Dubarry, J. P. Mialot, D. Remy, C. Richard, L. Martignat, X. Vignon, J. P. Renard
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A multidisciplinary research programme was developed to get a scientific expertise for the quality assessment of products obtained from cloned livestock. Thirty-seven bovine Holstein female clones of five different genotypes and their products were analysed in comparison with 38 control animals obtained by conventional artificial insemination and raised under the same conditions at the same experimental farm. Animal evaluation included over 150 criteria and more than 10 000 measurements to check the physiological status and health over a 3-year period. All the parameters studied were in the normal range for age and breed, but some significant differences were detected between clone and control groups in terms of delayed onset of puberty in clones, higher neutrophil counts in haematology or lower biochemical plasma concentrations of gamma glutamyl transferase. Milk and meat analyses were conformable to expected values. We, however, found some differences in fatty acid (FA) composition of milk and muscle suggesting a possible deviation in lipid metabolism as assessed by higher delta-9 desaturase activity indexes in both milk and muscles from clones compared with controls. Repeated muscle biopsies in the semitendinosus muscle of the same animals demonstrated a higher oxidative activity in muscle of young clones (8 months of age) compared with controls, suggesting a delayed muscle maturation in clones. Nutritional evaluation of milk and meat using the rat feeding trials did not show any difference between clone and control products for food intake, growth rate, body composition of the rats, nor for possible allergenicity. Possible reactivation of bovine endogenous retroviruses (BERVs) was analysed and compared between normal and cloned cattle. As expected, these BERV sequences are not transcribed and no RNA was detected in the blood of clones, donor animals or controls; therefore, it may be assumed that the sanitary risk associated with BERV sequences is not higher in cattle derived from somatic nuclear transfer than in cattle born from conventional reproduction. Our results confirm that the quality and safety of products (milk and meat) from adult and clinically healthy cloned cattle is globally similar to normal animals. However, from a strictly biological point of view, the slightly delayed maturation we observed in the muscle of clones together with some marginal differences identified in FA composition of both muscle and milk, point to the need for more refined analysis to totally exclude any risks from the consumption of those products.
Evolution du capteur électronique pour la dosimétrie des neutrons développé au LEPOFI
- M. BARELAUD, B. DUBARRY-CHABANAIS, D. PAUL, L. MAKOVICKA, J. L. DECOSSAS, J. C. VAREILLE
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- Journal:
- Radioprotection / Volume 28 / Issue 4 / October 1993
- Published online by Cambridge University Press:
- 26 May 2009, pp. 387-409
- Print publication:
- October 1993
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La dosimétrie neutronique des personnels à l'aide de dispositifs électroniques est étudiée depuis quelques années. Ces dispositifs offrent un avantage majeur : l'obtention d'une réponse en temps réel. Après une étude de faisabilité d'un système à double diode, fondé sur l'utilisation de la méthode différentielle, le capteur (convertisseur de polyéthylène (CH2)n avec une implantation d'ions 10B et diode silicium) a été expérimenté dans divers champs de neutrons et modélisé afin de confirmer et compléter les mesures. La contribution des photons γ de ces champs de neutrons est la principale perturbation pour la détermination de la réponse aux neutrons. La sensibilité aux neutrons Sn est de 1 impulsion cm-2 µSv-1 pour les thermiques et sur la gamme d'énergie 1,5 - 5 MeV avec un seuil énergétique à 125 keV pour les particules secondaires détectées. Lorsque les équivalents de dose γ et neutron (équivalent de dose ambient H* (10)) deviennent du même ordre de grandeur, la perte de sensibilité Sn est d'autant plus grande que la composante du spectre neutronique en dessous de 500 keV est plus importante par rapport à celle au-dessus de cette énergie. La sensibilité aux photons γ (Sγ) est de l'ordre de 300 impulsions cm-2 µSv-1 avec un seuil de coupure à 130 keV. La modélisation du capteur a été effectuée avec un code Monte-Carlo (EGS4) pour les photons γ et un programme développé au laboratoire (PNEDIOD) pour les neutrons. Une structure adéquate utilisant tous les paramètres optimisés issus de la modélisation améliorerait la discrimination (n-γ) en divisant la sensibilité Sγ par 15. Le seuil de détection énergétique de notre système pour les neutrons serait alors inférieur à 200 keV.