mohamed boufnichel - Academia.edu (original) (raw)

Uploads

Papers by mohamed boufnichel

Research paper thumbnail of Cryogenic Etching of Submicronic Features in Silicon Using Masks Based on Porous Polymer Films

ECS Meeting Abstracts, 2014

Deep silicon etching is typically used in applications requiring high aspect ratio structures, li... more Deep silicon etching is typically used in applications requiring high aspect ratio structures, like MEMS devices or 3D integration in microelectronics. In this last case, the most common technologies are Through-Silicon-Vias (TSV), used as electrical interconnects for die stacks in 3D packaging, and 3D capacitors, where very high specific capacities can be reached. The time-multiplexed Bosch process is widely used for deep etching and presents a good reproducibility if cleaning of the chamber is performed periodically. However, the etched structures exhibit polymer contamination, due to C4F8passivation steps, and scalloping, due to the etching-passivation cycles. Cryogenic silicon etching usually improves the etched profiles with smooth sidewalls and no polymer is utilized for passivation. The standard process is based on a silicon substrate cooled at a cryogenic temperature (-120°C to -100°C) and exposed to a monocyclic SF6/O2 plasma. The SiOxFypassivation layer, which prevents lat...

Research paper thumbnail of Modeling of silicon etching using Bosch process: Effects of oxygen addition on the plasma and surface properties

Journal of Vacuum Science & Technology A, 2018

Laser-assisted dry, wet texturing and phase transformation of flexible polyethylene terephthalate... more Laser-assisted dry, wet texturing and phase transformation of flexible polyethylene terephthalate substrate revealed by Raman and ultraviolet-visible spectroscopic studies

Research paper thumbnail of Modeling of ICP C4F8 plasma : effects of high RF power on the plasma electrical properties

Plasma Sources Science and Technology, 2019

International audienc

Research paper thumbnail of Single and multilayered materials processing by argon ion beam etching: study of ion angle incidence and defect formation

Journal of Micromechanics and Microengineering, 2015

Ion beam etching (IBE) is a very promising technique in microelectronics because of its capabilit... more Ion beam etching (IBE) is a very promising technique in microelectronics because of its capability to etch small patterns with a high resolution and inert materials. In this study, the angular incidence of an argon ion beam on the etch rate and uniformity is discussed in the case of several materials often used in microelectronics. The capability of the IBE technique to etch multilayered stack samples with positive anisotropic profiles was demonstrated on TiNiAu, TiNiCuAu, BST and PZT. Two typical defects involved in IBE processing (fences and not etched pattern foots) due to shadow masking and redeposition effect, are explained and solutions are presented to avoid them. Deep IBE was performed on GaN with an etch depth as high as 10 μm, using a 8 μm thick SiO2 mask. The etching of other mask materials, such as TiN, was investigated in order to improve the selectivity. Using a TiN mask, a selectivity to GaN as high as 5 is reported. Finally, the etch rate enhancement needed for deep etching was studied.

Research paper thumbnail of Connection ball positionning: method and device for integrated circuits

Research paper thumbnail of Gravure profonde cryogénique du silicium dans un réacteur ICP utilisant une chimie SF6/O2 : application pour la mise au point d'un procédé d'isolation électrique sur plaquette SOI

Http Www Theses Fr, 2002

Cette these concerne d'une part, l'etude des mecanismes de gravure et de passivation ayan... more Cette these concerne d'une part, l'etude des mecanismes de gravure et de passivation ayant lieu lors de la gravure du silicium (massif et SOI) par un plasma SF6/O2 et d'autre part, la mise au point d'un procede de gravure profonde optimise sur un reacteur industriel ICP. L'objectif est de graver des tranchees a fort facteur d'aspect (ouverture: 2 a 4 aem et profondeur ? 60 aem) en un temps competitif (vitesse de gravure ? 5aem/min) en vue de realiser des caissons d'isolation par tranchee sur silicium et sur SOI. La technique de gravure choisie est la cryogenie. Tres peu utilisee pour l'instant compare au procede bosch mais qui semble neanmoins prometteuse pour l'avenir. La premiere phase de ce travail a consiste a caracteriser le plasma electriquement et chimiquement par sonde de Langmuir et Spectroscopie d'Emission Optique. Les evolutions des caracteristiques du plasma en fonction des parametres de procede ont ete correlees a celles des profils de gravure. Il a ainsi ete possible d'expliquer le comportement de certains mecanismes impliques dans la gravure du silicium et de les maitriser afin d'atteindre l'objectif fixe par le cahier des charges. La seconde phase de l'etude concerne la mise au point d'un procede de gravure optimise sur substrat silicium et transposable ensuite sur des substrats SOI. Pour cela, il a fallu etudier et trouver la cause de certains effets negatifs comme le bowing et le notching. Finalement, la cryogenie s'avere avantageuse en tous points (pour ces objectifs precis de tranchee) par rapport au procede a temperature ambiante et le remplissage des profils par LPCVD se fait sans difficultes. Neanmoins, un tres bon controle de la temperature du substrat s'avere indispensable pour garantir une bonne uniformite des profils de gravure. Ce point (facteur limitant) qui concerne le porte-substrat est en cours d'etude par l'equipementier : une fois maitrisee, la cryogenie deviendra un atout majeur en gravure seche.

Research paper thumbnail of Silicon Microstructuring Method and Microbattery

Research paper thumbnail of Condenser in a monolithic circuit

Research paper thumbnail of Forming of oblique trenches

Research paper thumbnail of Mécanismes de gravure cryogénique du silicium utilisant une chimie SF6/O2

Research paper thumbnail of Study of SiOxFy passivation layer deposited in SiF4/O2 ICP discharge

Research paper thumbnail of Deep Inductively Coupled Plasma Etching of GaN

Research paper thumbnail of Applications of cryogenic plasma etching for microtechnology and advanced CMOS manufacturing

Research paper thumbnail of Deep Anisotropic Silicon Etch Method

The so -called STiGer process allowing to mix the CLEAN advantage of the cryogenic process & the ... more The so -called STiGer process allowing to mix the CLEAN advantage of the cryogenic process & the STABLE / INDUSTRIAL advantage of the Bosch process in the field of deep plasma etching of Silicon.

Research paper thumbnail of Impact of surfaces fluorination on GaN deep dry etching defects

Research paper thumbnail of Dry cryogenic etching of silicon trenches for MEM's applications

Research paper thumbnail of On the way to avoid deep GaN etching surface defects

Research paper thumbnail of Profile control of high aspect ratio trenches of silicon. II. Study of the mechanisms responsible for local bowing formation and elimination of this effect

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2003

Profile control of deep and narrow anisotropic trenches in silicon has been investigated in a low... more Profile control of deep and narrow anisotropic trenches in silicon has been investigated in a low-pressure high-density plasma reactor working with a SF 6 /O 2 plasma mixture. The aim is to achieve deep trenches with high aspect ratio (depth/widthϾ10), high anisotropy, high selectivity (silicon/SiO 2 maskϾ300:1), high etch rate ͑Ͼ5 m/min͒ and with no local bowing. This study focuses on a cryogenic etching method. In the previous article ͓M. Boufnichel et al., J. Vac. Sci. Technol. B 20, 1508 ͑2002͔͒ we presented a parametrical study of the evolution of local bowing as a function of the process conditions. Here we present a complete study of the mechanisms involved in the creation of local bowing at the top of deep narrow trenches, and in particular the effect ͑influence͒ of the characteristics ͑nature, thickness, and side slope͒ on local bowing. Explanations for the appearance of local bowing are given and targeted experiments are performed to eliminate it. The final performance shows that we are now able to etch a minimum of 60 m in depth for a 4 m trench aperture with no local bowing at a high etch rate of about 5.5 m/min with a cryogenic method in which no cleaning step is necessary unlike for the Bosh process ͓M. J. Walker, Proc. SPIE 4407 ͑2001͔͒.

Research paper thumbnail of Etching a single micrometer-size particle in a plasma

Physical Review E, 1999

Treatment of a single micrometer-size dust particle in a low-pressure radio-frequency discharge i... more Treatment of a single micrometer-size dust particle in a low-pressure radio-frequency discharge is presented. The particle is trapped in a potential well and its radius is accurately determined using angle-resolved Mie scattering. In an oxygen plasma, the particle radius can be decreased in a well-controlled way.

Research paper thumbnail of Multi-scale approach for simulation of deep silicon etching under ICP SF6/Ar plasma mixture

Deep etching of silicon represents a new challenge in the silicon semi-conductor manufacturing. I... more Deep etching of silicon represents a new challenge in the silicon semi-conductor manufacturing. Indeed, deep silicon etching is used to form through-silicon vias and connect stacked dies or wafers in 3D integration. In this context, computer simulation of plasma etching can contribute to the optimization of the etching process. In this study, we have developed a silicon etching simulator under ICP SF6/Ar plasma discharge. Such model is composed of three modules permitting to predict the 2D etched silicon morphology versus the operating conditions: plasma kinetic model, sheath model and etching model. The plasma kinetic model is based on the 0D global approach which allows the calculation of the average densities and fluxes of neutral and ion species as well as the electron density and temperature versus the ICP machine parameters. Such output parameters are introduced as input parameters in the sheath model and silicon etching model. Cellular Monte-Carlo method is used to describe t...

Research paper thumbnail of Cryogenic Etching of Submicronic Features in Silicon Using Masks Based on Porous Polymer Films

ECS Meeting Abstracts, 2014

Deep silicon etching is typically used in applications requiring high aspect ratio structures, li... more Deep silicon etching is typically used in applications requiring high aspect ratio structures, like MEMS devices or 3D integration in microelectronics. In this last case, the most common technologies are Through-Silicon-Vias (TSV), used as electrical interconnects for die stacks in 3D packaging, and 3D capacitors, where very high specific capacities can be reached. The time-multiplexed Bosch process is widely used for deep etching and presents a good reproducibility if cleaning of the chamber is performed periodically. However, the etched structures exhibit polymer contamination, due to C4F8passivation steps, and scalloping, due to the etching-passivation cycles. Cryogenic silicon etching usually improves the etched profiles with smooth sidewalls and no polymer is utilized for passivation. The standard process is based on a silicon substrate cooled at a cryogenic temperature (-120°C to -100°C) and exposed to a monocyclic SF6/O2 plasma. The SiOxFypassivation layer, which prevents lat...

Research paper thumbnail of Modeling of silicon etching using Bosch process: Effects of oxygen addition on the plasma and surface properties

Journal of Vacuum Science & Technology A, 2018

Laser-assisted dry, wet texturing and phase transformation of flexible polyethylene terephthalate... more Laser-assisted dry, wet texturing and phase transformation of flexible polyethylene terephthalate substrate revealed by Raman and ultraviolet-visible spectroscopic studies

Research paper thumbnail of Modeling of ICP C4F8 plasma : effects of high RF power on the plasma electrical properties

Plasma Sources Science and Technology, 2019

International audienc

Research paper thumbnail of Single and multilayered materials processing by argon ion beam etching: study of ion angle incidence and defect formation

Journal of Micromechanics and Microengineering, 2015

Ion beam etching (IBE) is a very promising technique in microelectronics because of its capabilit... more Ion beam etching (IBE) is a very promising technique in microelectronics because of its capability to etch small patterns with a high resolution and inert materials. In this study, the angular incidence of an argon ion beam on the etch rate and uniformity is discussed in the case of several materials often used in microelectronics. The capability of the IBE technique to etch multilayered stack samples with positive anisotropic profiles was demonstrated on TiNiAu, TiNiCuAu, BST and PZT. Two typical defects involved in IBE processing (fences and not etched pattern foots) due to shadow masking and redeposition effect, are explained and solutions are presented to avoid them. Deep IBE was performed on GaN with an etch depth as high as 10 μm, using a 8 μm thick SiO2 mask. The etching of other mask materials, such as TiN, was investigated in order to improve the selectivity. Using a TiN mask, a selectivity to GaN as high as 5 is reported. Finally, the etch rate enhancement needed for deep etching was studied.

Research paper thumbnail of Connection ball positionning: method and device for integrated circuits

Research paper thumbnail of Gravure profonde cryogénique du silicium dans un réacteur ICP utilisant une chimie SF6/O2 : application pour la mise au point d'un procédé d'isolation électrique sur plaquette SOI

Http Www Theses Fr, 2002

Cette these concerne d'une part, l'etude des mecanismes de gravure et de passivation ayan... more Cette these concerne d'une part, l'etude des mecanismes de gravure et de passivation ayant lieu lors de la gravure du silicium (massif et SOI) par un plasma SF6/O2 et d'autre part, la mise au point d'un procede de gravure profonde optimise sur un reacteur industriel ICP. L'objectif est de graver des tranchees a fort facteur d'aspect (ouverture: 2 a 4 aem et profondeur ? 60 aem) en un temps competitif (vitesse de gravure ? 5aem/min) en vue de realiser des caissons d'isolation par tranchee sur silicium et sur SOI. La technique de gravure choisie est la cryogenie. Tres peu utilisee pour l'instant compare au procede bosch mais qui semble neanmoins prometteuse pour l'avenir. La premiere phase de ce travail a consiste a caracteriser le plasma electriquement et chimiquement par sonde de Langmuir et Spectroscopie d'Emission Optique. Les evolutions des caracteristiques du plasma en fonction des parametres de procede ont ete correlees a celles des profils de gravure. Il a ainsi ete possible d'expliquer le comportement de certains mecanismes impliques dans la gravure du silicium et de les maitriser afin d'atteindre l'objectif fixe par le cahier des charges. La seconde phase de l'etude concerne la mise au point d'un procede de gravure optimise sur substrat silicium et transposable ensuite sur des substrats SOI. Pour cela, il a fallu etudier et trouver la cause de certains effets negatifs comme le bowing et le notching. Finalement, la cryogenie s'avere avantageuse en tous points (pour ces objectifs precis de tranchee) par rapport au procede a temperature ambiante et le remplissage des profils par LPCVD se fait sans difficultes. Neanmoins, un tres bon controle de la temperature du substrat s'avere indispensable pour garantir une bonne uniformite des profils de gravure. Ce point (facteur limitant) qui concerne le porte-substrat est en cours d'etude par l'equipementier : une fois maitrisee, la cryogenie deviendra un atout majeur en gravure seche.

Research paper thumbnail of Silicon Microstructuring Method and Microbattery

Research paper thumbnail of Condenser in a monolithic circuit

Research paper thumbnail of Forming of oblique trenches

Research paper thumbnail of Mécanismes de gravure cryogénique du silicium utilisant une chimie SF6/O2

Research paper thumbnail of Study of SiOxFy passivation layer deposited in SiF4/O2 ICP discharge

Research paper thumbnail of Deep Inductively Coupled Plasma Etching of GaN

Research paper thumbnail of Applications of cryogenic plasma etching for microtechnology and advanced CMOS manufacturing

Research paper thumbnail of Deep Anisotropic Silicon Etch Method

The so -called STiGer process allowing to mix the CLEAN advantage of the cryogenic process & the ... more The so -called STiGer process allowing to mix the CLEAN advantage of the cryogenic process & the STABLE / INDUSTRIAL advantage of the Bosch process in the field of deep plasma etching of Silicon.

Research paper thumbnail of Impact of surfaces fluorination on GaN deep dry etching defects

Research paper thumbnail of Dry cryogenic etching of silicon trenches for MEM's applications

Research paper thumbnail of On the way to avoid deep GaN etching surface defects

Research paper thumbnail of Profile control of high aspect ratio trenches of silicon. II. Study of the mechanisms responsible for local bowing formation and elimination of this effect

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2003

Profile control of deep and narrow anisotropic trenches in silicon has been investigated in a low... more Profile control of deep and narrow anisotropic trenches in silicon has been investigated in a low-pressure high-density plasma reactor working with a SF 6 /O 2 plasma mixture. The aim is to achieve deep trenches with high aspect ratio (depth/widthϾ10), high anisotropy, high selectivity (silicon/SiO 2 maskϾ300:1), high etch rate ͑Ͼ5 m/min͒ and with no local bowing. This study focuses on a cryogenic etching method. In the previous article ͓M. Boufnichel et al., J. Vac. Sci. Technol. B 20, 1508 ͑2002͔͒ we presented a parametrical study of the evolution of local bowing as a function of the process conditions. Here we present a complete study of the mechanisms involved in the creation of local bowing at the top of deep narrow trenches, and in particular the effect ͑influence͒ of the characteristics ͑nature, thickness, and side slope͒ on local bowing. Explanations for the appearance of local bowing are given and targeted experiments are performed to eliminate it. The final performance shows that we are now able to etch a minimum of 60 m in depth for a 4 m trench aperture with no local bowing at a high etch rate of about 5.5 m/min with a cryogenic method in which no cleaning step is necessary unlike for the Bosh process ͓M. J. Walker, Proc. SPIE 4407 ͑2001͔͒.

Research paper thumbnail of Etching a single micrometer-size particle in a plasma

Physical Review E, 1999

Treatment of a single micrometer-size dust particle in a low-pressure radio-frequency discharge i... more Treatment of a single micrometer-size dust particle in a low-pressure radio-frequency discharge is presented. The particle is trapped in a potential well and its radius is accurately determined using angle-resolved Mie scattering. In an oxygen plasma, the particle radius can be decreased in a well-controlled way.

Research paper thumbnail of Multi-scale approach for simulation of deep silicon etching under ICP SF6/Ar plasma mixture

Deep etching of silicon represents a new challenge in the silicon semi-conductor manufacturing. I... more Deep etching of silicon represents a new challenge in the silicon semi-conductor manufacturing. Indeed, deep silicon etching is used to form through-silicon vias and connect stacked dies or wafers in 3D integration. In this context, computer simulation of plasma etching can contribute to the optimization of the etching process. In this study, we have developed a silicon etching simulator under ICP SF6/Ar plasma discharge. Such model is composed of three modules permitting to predict the 2D etched silicon morphology versus the operating conditions: plasma kinetic model, sheath model and etching model. The plasma kinetic model is based on the 0D global approach which allows the calculation of the average densities and fluxes of neutral and ion species as well as the electron density and temperature versus the ICP machine parameters. Such output parameters are introduced as input parameters in the sheath model and silicon etching model. Cellular Monte-Carlo method is used to describe t...