Optimisation de la gravure de macropores ordonnés dans le silicium et de leur remplissage de cuivre par voie électrochimique (application aux via traversants conducteurs)

Ces travaux de thèse portent sur la fabrication de via traversants conducteurs, brique technologique indispensable pour l intégration des composants microélectroniques en 3 dimensions. Pour ce faire, une voie tout-électrochimique a été explorée en raison de son faible coût de fabrication par rapport aux techniques par voie chimique sèche. Ainsi, la gravure de macropores ordonnés traversants a été réalisée par anodisation du silicium en présence d acide fluorhydrique puis leur remplissage de cuivre par dépôt électrochimique. L objectif est de faire du silicium macroporeux une alternative crédible à la gravure sèche (DRIE) pour la structuration du silicium.Les conditions de gravure de matrices de macropores ordonnés traversants ont été étudiées à la fois dans des substrats silicium de type n et p faiblement dopés. La composition de l électrolyte ainsi que le motif des matrices ont été optimisés afin de garantir la gravure de via traversants de forte densité et à facteur de forme élevé. Une fois gravés, les via traversant ont été remplis de cuivre. En optimisant ces paramètres une résistance minimale égale à 32 m /via (soit 1,06 fois la résistivité théorique du cuivre à 20C) a été mesurée.These thesis works deal with the achievement of Through Silicon Via (TSV) essential technological issue for microelectronic device 3D integration. For this purpose, we opted for a full-electrochemical way of TSV production because of lower fabrication costs as compared to dry etching and deposition techniques. Indeed, ordered through silicon macropores were carried out by silicon anodization in hydrofluoric acid-containing solution and then filled by copper electrochemical deposition. The main objective is to determine if the macroporous silicon arrays can be a viable alternative as Deep Reactive Ion Etching (DRIE).The etching parameters of through silicon macropore arrays were studied both in low-doped n- and p-type silicon. The electrolyte composition as well as the density of the initiation sites was optimized to enable the growth of high aspect ratio, high density through silicon ordered macropores. After silicon anodization, through via were filled with copper. By optimizing the copper deposition parameters (bath composition and applied potential), the resistance per via was measured equal to 32 m (i.e. 1.06 times higher than the theoretical copper bulk resistivity).TOURS-Bibl.électronique (372610011) / SudocSudocFranceF

Copper-selective electrochemical filling of macropore arrays for through-silicon via applications

In this article, the physico-chemical and electrochemical conditions of through-silicon via formation were studied. First, macropore arrays were etched through a low doped n-type silicon wafer by anodization under illumination into a hydrofluoric acid-based electrolyte. After electrochemical etching, ‘almost’ through-silicon macropores were locally opened by a backside photolithographic process followed by anisotropic etching. The 450 × 450-μm² opened areas were then selectively filled with copper by a potentiostatic electrochemical deposition. Using this process, high density conductive via (4.5 × 10(5) cm(−)²) was carried out. The conductive paths were then electrically characterized, and a resistance equal to 32 mΩ/copper-filled macropore was determined

Porosity and thickness characterization of porous Si and oxidized porous Si layers – an ultraviolet-visible-mid infrared ellipsometry study

International audienc

Optimized plasma-polymerized fluoropolymer mask for local porous silicon formation

International audienc

Synthesis by solid route and physicochemical characterizations of blends of calcium orthophosphate powders and mesoporous silicon particles

The purpose of the study was to investigate the synthesis of economic calcium phosphate powders from recycled oyster shells, using a ball milling method. The oyster shell powder and a calcium pyrophosphate powder were used as starting materials and ball milled, then heat treated at 1,050°C for 5 h to produce calcium phosphate powders through a solid-state reaction. Electrochemically synthesized mesoporous silicon microparticles were then added to the prepared phosphate powders by mechanical mixer. The final powders were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy to analyze their chemical composition and determine the most suitable process conditions. The biocompatibility of the produced powders was also tested in vitro using murine cells and the results showed good biocompatibility

Optimization of ordered macropore etching in silicon and their filling copper by electrochemical way : application to through silicon via

Ces travaux de thèse portent sur la fabrication de via traversants conducteurs, brique technologique indispensable pour l’intégration des composants microélectroniques en 3 dimensions. Pour ce faire, une voie « tout-électrochimique » a été explorée en raison de son faible coût de fabrication par rapport aux techniques par voie chimique sèche. Ainsi, la gravure de macropores ordonnés traversants a été réalisée par anodisation du silicium en présence d’acide fluorhydrique puis leur remplissage de cuivre par dépôt électrochimique. L’objectif est de faire du silicium macroporeux une alternative crédible à la gravure sèche (DRIE) pour la structuration du silicium.Les conditions de gravure de matrices de macropores ordonnés traversants ont été étudiées à la fois dans des substrats silicium de type n et p faiblement dopés. La composition de l’électrolyte ainsi que le motif des matrices ont été optimisés afin de garantir la gravure de via traversants de forte densité et à facteur de forme élevé. Une fois gravés, les via traversant ont été remplis de cuivre. En optimisant ces paramètres une résistance minimale égale à 32 mΩ/via (soit 1,06 fois la résistivité théorique du cuivre à 20°C) a été mesurée.These thesis works deal with the achievement of Through Silicon Via (TSV) essential technological issue for microelectronic device 3D integration. For this purpose, we opted for a “full-electrochemical” way of TSV production because of lower fabrication costs as compared to dry etching and deposition techniques. Indeed, ordered through silicon macropores were carried out by silicon anodization in hydrofluoric acid-containing solution and then filled by copper electrochemical deposition. The main objective is to determine if the macroporous silicon arrays can be a viable alternative as Deep Reactive Ion Etching (DRIE).The etching parameters of through silicon macropore arrays were studied both in low-doped n- and p-type silicon. The electrolyte composition as well as the density of the initiation sites was optimized to enable the growth of high aspect ratio, high density through silicon ordered macropores. After silicon anodization, through via were filled with copper. By optimizing the copper deposition parameters (bath composition and applied potential), the resistance per via was measured equal to 32 mΩ (i.e. 1.06 times higher than the theoretical copper bulk resistivity)

Hybrid Porous Silicon - Silicon substrate for RF devices integration

International audienc

Titanium nitride / porous silicon electrode for microsupercapacitor applications

International audienceThis abstract deals with the investigation of a tunable way to prepare integrated micro-supercapacitors made of coated porous silicon (pSi). pSi allows developing a large specific surface area of the electrode material. To overcome the insulating behavior of the pSi, we chose to use Atomic Layer Deposition (ALD) to deposit a 2 nm thin layer of Titanium Nitride (TiN), to cover the pore sidewalls. SEM characterizations have been realized to confirm the conformal deposition of the conductive layer inside the porosity and electrochemical characterizations were carried out to determine the performances of supercapacitors. Capacity around 500 µF/cm² were obtained in Na2SO4 1M aqueous media