Classifications

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  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
  • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
  • H01L21/314—Inorganic layers
  • H01L21/316—Inorganic layers composed of oxides or glassy oxides or oxide based glass
  • H01L21/31695—Deposition of porous oxides or porous glassy oxides or oxide based porous glass
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  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02104—Forming layers
  • H01L21/02107—Forming insulating materials on a substrate
  • H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
  • H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
  • H01L21/02123—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon
  • H01L21/02126—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
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  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02104—Forming layers
  • H01L21/02107—Forming insulating materials on a substrate
  • H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
  • H01L21/02203—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates the layer being porous
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  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/02104—Forming layers
  • H01L21/02107—Forming insulating materials on a substrate
  • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
  • H01L21/0226—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process
  • H01L21/02282—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process liquid deposition, e.g. spin-coating, sol-gel techniques, spray coating
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  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
  • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
  • H01L21/76—Making of isolation regions between components
  • H01L21/762—Dielectric regions, e.g. EPIC dielectric isolation, LOCOS; Trench refilling techniques, SOI technology, use of channel stoppers
  • H01L21/76224—Dielectric regions, e.g. EPIC dielectric isolation, LOCOS; Trench refilling techniques, SOI technology, use of channel stoppers using trench refilling with dielectric materials
• • H—ELECTRICITY
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  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
  • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
  • H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
  • H01L21/76801—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing
  • H01L21/7682—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing the dielectric comprising air gaps
• • H—ELECTRICITY
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  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
  • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
  • H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
  • H01L21/76838—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors
  • H01L21/76877—Filling of holes, grooves or trenches, e.g. vias, with conductive material
• • H—ELECTRICITY
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  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L23/00—Details of semiconductor or other solid state devices
  • H01L23/52—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames
  • H01L23/522—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body
  • H01L23/532—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body characterised by the materials
  • H01L23/53204—Conductive materials
  • H01L23/53276—Conductive materials containing carbon, e.g. fullerenes
• • H—ELECTRICITY
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  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
  • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
  • H01L21/76—Making of isolation regions between components
  • H01L21/764—Air gaps
• • H—ELECTRICITY
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  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
  • H01L2221/10—Applying interconnections to be used for carrying current between separate components within a device
  • H01L2221/1068—Formation and after-treatment of conductors
  • H01L2221/1094—Conducting structures comprising nanotubes or nanowires
• • H—ELECTRICITY
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  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/0001—Technical content checked by a classifier
  • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Definitions

• the invention relates to a method of forming porous material in at least one microcavity or a micropassage of a support, said microcavity or said micropassage opening on a surface of the support.
• These low dielectric constant materials are typically used in the electrical insulation of the components in the form of integrated patterns in the substrate or in the interconnection structures of the integrated circuits to isolate the lines of metallic material and reduce their electromagnetic coupling.
• the vacuum having the lowest dielectric constant a low dielectric constant material is obtained by creating porosity in a dielectric material, i.e. incorporating vacuum or gas into the material. So, by maximizing the porosity in the insulating material, it is possible to strongly reduce the dielectric constant of the final material.
• the siliconized silicon oxide SiOC has, in the bulk state, a dielectric constant equal to 3.2.
• the dielectric constant is equal to 2.5.
• porous materials are obtained by plasma enhanced chemical vapor deposition or spin coating.
• these techniques can not fill small microcavities, making these techniques unsuitable.
• the object of the invention is the formation of a porous material in a microcavity in an industrial and easy manner.
• the method according to the invention is characterized by the appended claims and more particularly by the fact that said surface being in contact with an aqueous solution comprising a plurality of particles in suspension, the method simultaneously comprises the application of a pressure perpendicular to the plane of the support, between a fabric and a surface of the support having the microcavity or the micropassage and a relative movement of the tissue and the surface, parallel to the plane of the support, for introducing at least one particle into each microcavity or micropassage and in that the porous material is a catalyst material for the growth of nanowires or nanotubes.
• FIGS. 4 and 5 show in section, schematically, the successive steps of a variant of the embodiment method according to the invention
• FIGS. 6 and 7 show in section, schematically, the successive steps of a second variant of the embodiment method according to the invention
• FIGS. 8 and 9 schematically represent, in section, the successive steps of a third variant of the embodiment method according to the invention.
• FIGS. 10 to 12 show in section, schematically, the successive steps of a fourth variant of the embodiment method according to the invention.
• microcavities 1 are formed in a support 2 and open on one of its faces, the main face 2a.
• the support 2 may be constituted by a substrate, for example a silicon substrate.
• a plurality of layers may also be deposited on the substrate and form, for example, metal interconnect levels.
• Microcavities 1 are formed conventionally, for example, by photolithography and etching and can be made directly in the substrate or in the layers deposited on the substrate.
• the face of the support 2 comprising the microcavities 1 is then subjected to a chemical mechanical deposition process, which is close to chemical mechanical polishing processes.
• a chemical mechanical deposition process which is close to chemical mechanical polishing processes.
• the surface on which the microcavities 1, the main face 2a, comes into contact is put in contact with a polishing cloth 3, for example a piece of polyurethane, covered with an aqueous solution which comprises particles 4.
• a force is applied to the support along an axis forming a non-zero angle relative to the plane of the support.
• This force results in the creation of a pressure P between the support 2 and the fabric 3, for example perpendicular to the plane of the support 2.
• the support 2 moves, for example by rotation, relative to the fabric 3 or Conversely.
• the displacement is advantageously carried out in a plane parallel to the plane of the support 2.
• the chemical mechanical polishing is described by Xie et al "Effects of particle size, polishing pad and abrasive contact polishing", WEAR 200 ( 1996) 281-285.
• a porous material is thus formed inside the microcavity. It is constituted by the particle or particles and the vacuum (or gas) which occupies the remaining volume of the microcavity.
• the porous material can completely or partially fill the microcavity 1.
• the porous material can be constituted by a single particle, but, in a conventional manner, it is formed by a plurality of particles 4.
• the microcavity which is filled by the particle or particles ( s) then forms a pattern of porous material whose dimensions are defined by the initial dimensions of the microcavity 1.
• these particles 4 are compressed in the microcavity to thereby form porous material units mechanically more resistant.
• the microcavities 1 are not filled with a material that must be flattened, but they are left empty so that the particles 4 contained in the aqueous solution are introduced inside the microcavities.
• the chemical-mechanical deposition can be achieved by conventional chemical mechanical polishing equipment, for example by Mirra or Reflexion type equipment from the Applied Materials® company or by Megapol M550 equipment from the Alpsitec company or by equipment. Frex type of Ebara company.
• the support 2 is integral with a movable head 5, which makes it possible to exert a pressure P between the face of the support comprising the microcavities 1 and the fabric 3 ("pad" in English) on which rests the support ( Figure 2).
• the pressing pressure exerted by the support head on the support 2 is between 0.02 and 1daN / cm 2 . This pressing pressure makes it possible to introduce the particles 4 into the microcavities 1 and to compress them.
• modulating the value of the pressure of support it is possible to modulate the final porosity of the porous material, that is to say the proportion of vacuum in the final material.
• the particles 4 can be compacted in the microcavity 1, they then provide mechanical stability to the building thus formed, which is particularly advantageous for forming vertical stacks, for example, in interconnection structures with air cavities .
• the fabrics 3 used for the chemical mechanical deposition are identical to those used in conventional polishing processes. Conventionally, the characteristics of the fabric 3 depend on the desired application, the materials on the surface of the substrate and the dimensions of the microcavities to be filled.
• microcavities 1 If the smallest dimension of the microcavities 1 is greater than 10 .mu.m, 3 so-called "flattening" fabrics made of polyurethane, with a hardness classified as “Sore D” between 50 and 70, a density of between 60 and 90 mg / cm 3 and a compressibility of less than 4% are used.
• an IC1000 TM commercial fabric from Rohm & Haas is used.
• microcavities 1 If the smallest dimension of the microcavities 1 is less than 10 .mu.m, 3 so-called “medium” fabrics, with a hardness classified as “shore A” between 50 and 70, a density of between 20 and 40 mg / cm 3 and compressibility included between 10 and 25% are used.
• a Suba IV TM commercial fabric from Rohm & Haas is used.
• the dimensions of the microcavities 1 are of the order of one micron and / or if the face of the support, in contact with the fabric 3, comprises ductile materials that may be scratched by particles
• polishing fabrics 3 called “ are used, with a hardness classified in "shore A” from 50 to 80, a density of less than 20 mg / cm 3 , and a compressibility greater than or equal to 30% are used.
• a commercial Politex TM fabric 3 from Rohm & Haas is used.
• the support 2 is in contact with an aqueous solution.
• the deposit uses an aqueous suspension of colloidal particles, anionic or cationic, whose pH is between 1, 5 and 12 to obtain a stable suspension of particles.
• the pH modulation makes it possible to set the zeta potential which controls the separation of the particles 4 in the aqueous solution.
• the particles 4 suspended in the aqueous solution may be pure or consist of a core material covered by a coating material. If the particles 4 are pure, they are, for example, silica, carbon, cerium oxide, alumina, polymeric material or different metals, for example Fe, Co, Au, Pd, Ni, Pt, etc. If the particles 4 are coated, the coating material is, for example, alumina, cerium oxide or iron oxide. These are, for example, particles of silica or of polymer materials or compounds coated with alumina or with cerium oxide. The use of a coating material makes it possible to vary the zeta potential and thus allows easy separation of the elementary particles of the colloidal suspension.
• the size of the elementary particles 4 is advantageously between 3 and 300 nm. Moreover, the mass percentage of the particles 4 in the aqueous solution is advantageously between 0.0001 and 50%.
• the particles 4 may be spherical or any shape.
• aqueous solutions Klebosol TM 1508-35 and T605 can be used.
• the commercial aqueous solution Klebosol TM 1508-35 is marketed by the company Rohm & Haas and comprises 30% by weight of silica particles having a diameter of 35 nm, in an anionic solution with a pH of about 10 adjusted with NH 4 OH.
• the commercial aqueous solution T605 is marketed by Hitachi Chemical and comprises 0.1% by weight of silica particles having a diameter of 90 nm in an anion solution with a pH of about 6.5.
• the chemical-mechanical deposition is advantageously carried out with an aqueous solution flow rate of between 5 and 300 ml / min for substrates varying between 1 and 450 mm.
• a relative speed of a point of the substrate with respect to a point of the fabric 3 is then between 0.1 and 0.3 m / s.
• the temperature of the deposit is between 2 and 70 ° C.
• the flow of the supply in aqueous solution is adjusted to ensure a renewal of the particles and to ensure an excess of particles 4 in the pores of the polishing cloth.
• a bearing pressure of the order of 0.1 daN / cm 2 a speed of 1 m / s, a flow rate of aqueous solution of 150 ml / min for substrates of 200 mm in diameter and a temperature of 52 0 C are used to achieve the chemical mechanical deposition.
• silicon oxide particles 4 having an average diameter of the order of 35 nm are used with microcavities of the order of 150 nm in diameter.
• the Klebosol TM 1508-35 aqueous solution is advantageously used.
• the polishing cloth 3 removes the particles 4 from the aqueous solution only on the parts in contact with the support, that is to say on the parts of the support 2 which border microcavities and / or in areas where the porous material protrudes from the plane of the support.
• the removal of material is a function of the process conditions (support pressure, material of the particles, aqueous solution, etc.) and the type of material present on the surface of the support.
• a reinforcing material 6 is then advantageously used (FIGS. 1 to 3).
• This reinforcing material 6 is chosen so as to be resistant to the chemical-mechanical process, so as to reduce, or even completely eliminate, the removal of material on the parts of the support which are in contact with the fabric 3 and the aqueous solution.
• the reinforcing layer 6 is formed on the surface and the microcavities 1 are then etched in the support 2 through the reinforcing layer.
• the reinforcing layer is, for example, silicon nitride.
• the internal walls of the microcavities 1 are covered by a layer of cover material 7, for example, by an insulating material, for example silicon oxide.
• a layer of cover material 7 for example, by an insulating material, for example silicon oxide.
• the material of the support 2 is not chemically compatible with the material used for the particles 4, these particles do not adhere to the surface of the material of the cavities and the particles are removed during rinsing with water at the end of polishing and / or during cleaning by brushing and drying the plate.
• the layer 7 is therefore advantageously used depending on the materials present and the desired applications. Layer 7 can be used for particle adhesion, but also for electrical insulation, or as a barrier layer to dopant diffusion or to the formation of metal dendrites.
• the pressure exerted by the fabric 3 on the particles arranged in the microcavities causes the creation of bonds between the particles and with the walls of the microcavities. During drying, the particles remain chemically or electrostatically bound to each other and to the walls of the microcavity. The pressure exerted on the particles can also cause sintering of the particles, thus improving the mechanical strength of the entire microcavity.
• the number of particles 4 disposed in the microcavity 1 is a function of the dimensions of the microcavity 1, the dimensions of the particles 4 and the pressure exerted on the particles.
• a particle by microcavity it is advantageous to opt for a particle which has substantially the same dimension as the microcavity.
• To obtain two particles per microcavity it is advantageous to choose particles, supposedly spherical, which have diameters substantially equal to two-thirds of the size of the microcavity, supposed cubic.
• the volume occupied by the particles can not exceed, theoretically, 74% without compression.
• a compactness equal to 74% is obtained with so-called "hexagonal compact” or "cubic face-centered” stacks.
• the porous dielectric material units have at least 26% porosity.
• the actual compactness of such structures does not exceed 70%.
• the cubic microcavity can contain only one particle and the porosity reaches 50%. In this way, it is therefore possible to modulate the porosity by controlling the size of the particles in the microcavity. It is also possible to modulate the number of particles present in the cavity even if the particles are not spherical.
• the porous material may be a dielectric material, it is then formed by particles 4 of dielectric material and / or covered by a dielectric material.
• the particles are, for example, silica, cerium oxide, alumina or polymer material if they are pure. However, the particles may also be of conductive material, for example carbon, iron, cobalt, platinum, nickel, etc. covered by a dielectric material.
• the microcavities 1 can be formed in a silicon substrate and be filled with a porous dielectric material. In this way, patterns of porous dielectric material electrically isolate active components.
• the microcavities are filled with particles 4 made of silicon oxide.
• the layer 7 has a dual function, it allows an electrical insulation of the microcavity and an improvement of the adhesion of the particles.
• the substrate advantageously comprises the reinforcing layer 6 of silicon nitride and the layer 7 can be formed by oxidation or by deposition after the formation of the layer 6. During the chemical mechanical deposition, the particles are adhered to the thin layer 7 covering the cavity.
• the bonding is carried out chemically by forming SiOH bonds between the two SiO 2 materials, the particles 4 and the layer 7, by the presence of water and the pressing pressure of the particles on the layer 7. Bonding is also performed mechanically by means of the pressure of support which keeps the particles 4 glued in the microcavities. Particles are protected in the background microcavities of tissue displacement at the surface of the sample. They are also protected from the mechanical action of the displacement of the fabric by the very large number of particles which form a viscous protective film. The thickness of this protective film depends on the size, and the concentration of the silica particles in the aqueous solution, the material and the shape of the polishing cloth and the pressure parameters, the velocity of the fabric relative to the substrate .
• the microcavities 1 can also be made in a metallic interconnection structure of the support 2, as illustrated in FIGS. 4 and 5.
• the metal interconnection structure comprises patterns made of metallic material 8, for example copper or aluminum, which are separated by an insulating material and / or sacrificial 9 for example silica or SiOC which may also be porous.
• the insulating and / or sacrificial material 9, made of carbonaceous silica (SiOC), may be, for example, a silica of the BD1® and BD2® type sold by the company Applied Materials®.
• the metallic material patterns 8 coated with sacrificial and / or insulating material 9 are conventionally obtained by photolithography, etching, deposition and chemical mechanical polishing steps.
• the microcavities 1 are then formed between the metallic material patterns 8.
• the microcavities 1 may be conventionally formed in the material 9, as shown in FIG. 1.
• the microcavities 1 are preferably formed by eliminating at least partially the insulating material and / or sacrificial 9. The elimination is carried out by any suitable technique, for example by means of hydrofluoric acid if the insulator is silica.
• the sacrificial and / or insulating material 9 can thus be totally or partially eliminated according to the chosen application.
• the microcavities 1 are then filled, by mechanical-chemical deposition, with a porous dielectric material, constituted as previously by the particles 4.
• the layer of particles 4 which fills the microcavities is dense enough and solid to be able to form a new level above. metal interconnection (FIG. 5).
• the layer 7 can be used as diffusion barrier layer for the realization of interconnection structures of copper or aluminum.
• the particles used are, for example, silica particles with or without carbon dopants mechano-chemically deposited between the metal lines to form the porous insulation.
• the porous insulating material conventionally has a dielectric constant of the order of 2 and has a mechanical rigidity which allows the formation of multiple levels of interconnections.
• the porous material formed in the microcavities 1 can also be used as a catalyst material for locating the growth of nanotubes or nanowires.
• the support 2 comprising the microcavities 1 filled with the porous catalyst material is subjected to a growth process of nanotubes or nanowires.
• the nanowires or nanotubes can be electrically conductive or not.
• the growth of silicon nanowires can be obtained from a porous catalyst material comprising gold particles 4.
• the growth of carbon nanotubes is advantageously obtained from a porous catalyst material which comprises particles 4 made of Fe 1 Ni and / or Co.
• the porous catalyst material may be in any case material adapted to the growth of nanowires and / or nanotubes and in particular silicon oxide.
• the growth of carbon nanotubes can be carried out by any suitable technique, for example by chemical vapor deposition CVD, plasma-enhanced chemical vapor deposition PECVD, Electron Cyclotron Resonance PECVD, chemical vapor deposition with hot filament Laser assisted chemical vapor deposition ...
• a technique allowing the growth of carbon nanotubes from the catalyst and at a temperature below 900 ° C. is used.
• the gases used during the formation of carbon nanotubes may be CO, C 2 H 2 , CH 4 , Fe (C 5 H 5 ) 2 , xylene, metallocenes, alcohols in the gaseous state and all carbonaceous gases. , H 2 , NH 3 , H 2 O, O 2 or a mixture of these gases.
• Carbon can also be provided by a graphite floor, bombarded by a plasma.
• first 10 and second 11 materials are formed on the support 2 and structured so as to form the microcavities 1.
• the bottom of the microcavities 1 is then formed by the first material 10 and the walls by the second material 11.
• the first and second materials 10 and 11 may be insulating or conductive materials.
• the first and second materials 10 and 11 may be identical or different and are, for example, Al 2 Oe, SiO 2 , SiN, SiCN, SiC, SiOC or polymer material.
• the porous catalyst material then fills the cavities and allows the growth of nanotubes or nanowires 12.
• the first material 10 is also conductive, for example, in Cu, Al, Fe, Co, Ni, Pd. , Pt, W, Cr, TiN, TaN, Ta, Ti, Ru.
• first and second materials 10 and 11 form part or form an interconnection structure.
• the first material 10 is advantageously copper and forms patterns which are covered by the second material 11, silicon oxide or a material with low dielectric permittivity.
• the microcavities 1 are then conventionally formed in the silicon oxide above copper patterns.
• a layer of hooked and / or a barrier layer (not shown) is then deposited in the bottom of the microcavities 1.
• the hooked layer reinforces the adhesion of the barrier layer to the layer of first material 10.
• the hooked layer is, for example, Ta, TaN, TiN, Ti, Al, Ru, Mn, Mo, Cr, its thickness is preferably less than 10nm and can go to the deposition of an atomic layer.
• the barrier layer generally used to prevent interdiffusion of the catalyst material with the first material 10, is for example Al, TiN, Ti, Ta, TaN, CoWP, CoWB, NiMoP.
• the thickness of the barrier layer is typically less than 10 nm.
• the porous material is formed from the compacted particles 4 in the microcavities 1.
• the nanotubes or nanowires 12 grow vertically from the particles 4.
• the density of nanotubes or nanowires 12 from the pattern of porous material may vary.
• the porous catalyst material is also electrically conductive.
• the growth of nanotubes or nanowires is mostly done by a growth called "tip growth"("tipgrowth” in English).
• the catalyst particle is permanently at the tip of the nanotube which rises as the growth progresses. As a result, the nanotubes can grow from the bottom of the cavity regardless of the pore diameter.
• the microcavity 1 can be cleaned in order to remove residues contained in the aqueous solution and which have been introduced with the particles 4.
• the microcavities are then rinsed with a chemical solution which can be a mixture water, hydrofluoric acid, sulfuric acid, hydrochloric acid and / or hydrogen peroxide. It is also possible to clean the cavity by means of a heat treatment under oxygen at a temperature above 200 0 C, or to use a remote plasma of oxygen.
• the nanotubes or nanowires can then be formed as before.
• the technique of cleaning the microcavity is adapted to the material that makes up the porous material.
• the first material 10 is disposed between the support 2 and the second material 11 and can form a continuous layer or patterns.
• the microcavities 1 are formed in the second material 11 and their bottom is made by the first material 10.
• the porous catalyst material is then formed in the microcavities 1 ( Figure 8).
• the support 2 is subjected to a chemical degradation agent which passes through the porous material and which degrades the first material 10.
• the first material 10 being at least partially removed, air cavities are formed in the first material 10.
• the latter can also be completely eliminated and the second material 11 is then supported by means of suspension structures (not shown).
• the first material 10 may be, for example, silicon oxide and the second material 11 silcium nitride or metal.
• the support 2 is then subjected to the growth process of nanotubes or nanowires 12.
• the growth of these latter takes place from the porous catalyst material on the two free surfaces and in two directions. opposed.
• a portion of the nanotubes or nanowires grows vertically upwards and another part increases downwards, in FIG. 9, until the support 2 is connected.
• the nanotubes or nanowires connect the support 2 in connection zones. electrical component of active components ( Figure 9).
• the nanotubes or nanowires may also connect metal material patterns belonging to a lower metal level of the support 2.
• the contribution of material for the growth of the nanotubes / son can be achieved by the pores or else by another cavity.
• the porous material obtained can then have an increased mechanical strength.
• the dielectric constant of the porous material obtained can also be modulated by choosing the size and composition of the particles that compose it.
• Nanotubes or nanowires can also be used as thermal conductors to evacuate heat.
• the recesses are through orifices which pass through the support 2 and form all or parts of micropassages 13.
• the micropassage realization of porous material is similar to the formation of the porous material in the microcavities.
• a holding layer 14 is advantageously formed on the opposite face 2b of the support.
• the micropassages 13 are then made from the main face 2a until the holding layer 14 is reached.
• the holding layer may be partially etched.
• the micropassages 1 are thus formed in the support 2 through the through orifices, but are covered by the holding layer 14.
• the holding layer 14 provides an ease of embodiment because it can be removed easily.
• the layer 14 provides mechanical support, but can also serve as a stop layer for the formation of nanotubes or for a polishing step.
• the main face 2a of the support which comprises micropassages 13, is then subjected to a chemical mechanical deposition process, which is close to chemical mechanical polishing processes.
• a chemical mechanical deposition process which is close to chemical mechanical polishing processes.
• the first main face 2a, on which the micropassages 13 open is brought into contact with the fabric 3 covered by the aqueous solution which comprises the particles 4.
• a force is applied on the support along an axis forming a non-zero angle relative to the plane of the support. This force results in the creation of a pressure P between the support 2 and the fabric 3, advantageously perpendicular to the plane of the support 2.
• At least one particle 4 is introduced into each micropassage 13, which was initially empty.
• a porous material is thus formed inside the micropassage. It is constituted by the particle or particles and the vacuum (or gas) which occupies the remaining volume of the micropassage.
• the porous material may completely or partially fill the micropassage 13.
• the porous material may consist of a single particle, but conventionally it is formed by a plurality 4.
• these particles 4 are compressed in the micropassage to thereby form porous material units mechanically more resistant.
• the porous material is a permeable material. Indeed, the homogeneous arrangement of the pores in the porous material allows the flow of a fluid through the latter.
• the chemical-mechanical deposition can be achieved, as before, by conventional mechanical-chemical polishing equipment under the same conditions.
• the fabrics used for chemical mechanical deposition are also identical to those used in conventional polishing processes.
• the characteristics of the fabric depend on the desired application, the materials on the surface of the support and the dimensions of the micropassages to be filled.
• the pressing pressure makes it possible to introduce the particles 4 into the micropassages 13, to compress them. By modulating the value of the pressing pressure, it is possible to modulate the final porosity of the porous material, that is to say the proportion of vacuum in the final material. If the retaining layer 14 is not deposited on the support, the support head comes to cover the micropassages at the opposite face 2b and allow the application of pressure on the particles in the micropassages.
• the particles 4 suspended in the aqueous solution may be pure or consist of a core material covered by a coating material. If the particles 4 are pure, they are, for example, silica, carbon, cerium oxide, titanium oxide, alumina, polymeric material or different metals, for example, Fe, Co, Au, Pd , Ni, Pt, Ru, Sn, Mo, ZnO, Ce, etc. If the particles 4 are coated, the coating material is, for example, alumina, cerium oxide or iron oxide. These are, for example, particles of silica or of polymer materials or compounds coated with alumina or with cerium oxide. The use of a coating material allows to vary the zeta potential and thus allows easy separation of the elementary particles of the colloidal suspension.
• the size of the elementary particles 4 is advantageously between 3 and 300 nm. Moreover, the mass percentage of the particles 4 in the aqueous solution is advantageously between 0.0001 and 50%.
• the particles may be spherical or of any shape.
• Klebosol TM 1508-35 and T605 can be used.
• the polishing cloth 3 removes the particles 4 from the aqueous solution only on the parts in contact with the support, that is to say on the parts of the support 2 which border micropassages and / or in areas where the porous material exceeds the plane of the support.
• the removal of material is a function of the process conditions (support pressure, material of the particles, aqueous solution, etc.) and the type of material present on the surface of the support.
• the reinforcing material 6 is advantageously used (FIG. 1).
• the reinforcing layer 6 is formed on the surface 2a and the micropassages 13 are etched in the support 2 through the reinforcing layer.
• the sidewalls of micropassages 13 are covered by the layer of cover material (not shown), for example, by an insulating material, for example, silicon oxide.
• the cover layer is removed in the bottom of the micropassage 13.
• the bottom of the layer is etched by plasma as for the formation of spacers in the field of microelectronics.
• the covering material is advantageously used.
• the pressure exerted by the fabric 3 on the particles arranged in the micropassages causes the creation of bonds between the particles and with the walls of the micropassages. During drying, the particles remain chemically or electrostatically bound to each other and to the walls of the micropassage. The pressure exerted on the particles can also cause sintering of the particles, thus improving the mechanical strength of the entire micropassage.
• the number of particles 4 arranged in the micropassage 1 and the pore size of the porous material obtained are a function of the dimensions of the micropassage 1, the dimensions of the particles 4 and the pressure exerted on the particles.
• the micropassages are filled with few particles.
• the exchange surface must be large, the micropassages are then filled with a very large number of particles.
• the porous material may be a dielectric material, it is then formed by particles 4 of dielectric material and / or covered by a dielectric material.
• the particles are, for example, silica, cerium oxide, alumina or polymer material if they are pure. However, the particles may also be of conductive material, for example carbon, iron, cobalt, platinum, nickel, etc. covered by a dielectric material.
• the porous material may also be a catalyst material which allows decomposition reactions of gases or compounds in the liquid or gaseous route. The production of a membrane comprising areas of porous catalyst material is particularly interesting because, the process temperature being low, typically less than 100 0 C, the particles of catalyst material are kept fully active.
• the micropassages 13 filled with the porous material form passages between the two main faces 2a and 2b of the support 2.
• the support 2 and the holding layer 14 are different materials, however, they may also include the same constituents in different proportions.
• the holding layer 14 is, for example, Al 2 O 3 , SiO 2 , SiN, SiCN, SiC, SiOC or polymer material.
• the holding layer 14 may also be a metal.
• the holding layer 14 is then removed at least one level of the passages ( Figure 13) by any suitable technique. This removal of the holding layer allows the flow of a fluid from one of the main faces of the membrane, for example the face 2b, to the other face 2a.
• the holding layer 14 may be, for example, silicon oxide and its degradation is then carried out using hydrofluoric acid.
• the holding layer has an etching selectivity with respect to the porous material and the support 2.
• the retaining layer 14 is permeable to the fluid that must flow through the membrane, it may be left (FIG. 12) or removed (FIG. 14) to prevent excessive losses of the membrane. .
• a permeable layer 15 may be formed on at least one face 2a or 2b of the membrane.
• this permeable layer 15 is made of electrically conductive material, however, it can also be made of semiconductor or dielectric. Even more advantageously, the permeable layer is a layer which allows the conduction of protons in the membrane.
• the permeable layer is then chosen from among the nation®, polybenzimidazoles, sulphonated polyetheretherketones and sulphonated polyimides.
• the membrane may advantageously be used in a fuel cell.
• the micropassage 13 can be cleaned in order to remove residues contained in the aqueous solution and which have been introduced with the particles 4.
• the micropassages are then rinsed with a chemical solution.
• a chemical solution which may be a mixture of water, hydrofluoric acid, sulfuric acid, hydrochloric acid and / or hydrogen peroxide. It is also possible to clean the passage by means of an oxygen thermal treatment at a temperature above 200 ° C, or to use a remote plasma of oxygen.
• the porous material formed in the micropassages 13 can also be used as a catalyst material for locating the growth of nanotubes or nanowires 12, as illustrated in FIGS. 16 and 17.
• the support 2 comprising the micropassages 13 filled with the material porous catalyst is subjected to a growth process of nanotubes or nanowires.
• the nanowires or nanotubes can be electrically conductive or not. It is possible to graft nanoparticles, for example Pt or Ru, onto the nanotubes. This application is particularly interesting for membranes with oxidation of methanol in fuel cells. Increasing the contact area slows the flow around micropassages and thus increases the efficiency of the membrane.
• the density of nanotubes or nanowires depends directly on the density and size of the particles.
• the holding layer 14 is present during the growth process of nanotubes or nanowires, the growth of these latter takes place from the free surface in a substantially vertical direction relative to the plane of the support 2. If the holding layer is eliminated before growth, the nanotubes or nanowires grow from the two free surfaces, that is to say on each main face of the membrane.
• the modulation in chemical composition of the particles makes it possible to produce multispecific membranes, that is to say membranes that are capable of catalyzing several species mixed in an initial composition.
• the modulation of the particle size (even if they are of the same chemical composition) makes it possible to vary the reactivity of the particles.
• the modulation of the particle size makes it possible to obtain a wide range of surface energy and to offer a wide range of reactivity through the same micropassage.
• the exceptional reactivity of nanoparticles is related to the fact that they have a high ratio between the surface atoms which have free atomic bonds and the atoms of volumes which have no free bonds. Reactivity increases as the number of free bonds increases. As a result, it is therefore possible to catalyze a given species with high probability using a wide range of nanoparticle sizes.
• a membrane may be formed, the membrane being constituted by an impermeable support which has through passages, these through passages being filled with a porous material.

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