WO2006117625A2 - Equipement et procede de traitement par implantation d'ions de dispositifs medicaux - Google Patents

Equipement et procede de traitement par implantation d'ions de dispositifs medicaux Download PDF

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Publication number
WO2006117625A2
WO2006117625A2 PCT/IB2006/001060 IB2006001060W WO2006117625A2 WO 2006117625 A2 WO2006117625 A2 WO 2006117625A2 IB 2006001060 W IB2006001060 W IB 2006001060W WO 2006117625 A2 WO2006117625 A2 WO 2006117625A2
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Prior art keywords
holder
target
chamber
ion beam
disk
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PCT/IB2006/001060
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English (en)
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WO2006117625A3 (fr
Inventor
Alexander V. Samkov
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Samkov Alexander V
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Publication of WO2006117625A2 publication Critical patent/WO2006117625A2/fr
Publication of WO2006117625A3 publication Critical patent/WO2006117625A3/fr

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
    • A61L31/08—Materials for coatings
    • A61L31/082—Inorganic materials
    • A61L31/084—Carbon; Graphite
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/28—Materials for coating prostheses
    • A61L27/30—Inorganic materials
    • A61L27/303—Carbon
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L29/00—Materials for catheters, medical tubing, cannulae, or endoscopes or for coating catheters
    • A61L29/08—Materials for coatings
    • A61L29/10—Inorganic materials
    • A61L29/103—Carbon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/48—Ion implantation
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/50—Substrate holders
    • C23C14/505—Substrate holders for rotation of the substrates

Definitions

  • Titanium is often used in the manufacture of medical devices. Titanium-based articles, however, tend to encourage thrombogenesis. This tendency is particularly undesirable in devices used in the blood circulation system, such as heart valves.
  • One approach for reducing the thrombogenicity of titanium-based devices includes coating the device with a diamond-like carbon (DLC) film, formed, for example, by chemical vapor deposition techniques.
  • DLC diamond-like carbon
  • a titanium-based component is heated in a vacuum chamber to approximately 600 - 650 degrees centigrade (°C). Silicon is deposited onto the component, and the component is simultaneously bombarded with a beam of energetic ions to form a metal-silicide bonding layer.
  • the component is then cooled, e.g., to about 80°C, and a DLC precursor is condensed onto the metal-silicide bonding layer.
  • the precursor is simultaneously bombarded with a beam of energetic ions, preferably nitrogen ions, to form a DLC coating.
  • Patent document GB 2,287,473 A published on September 20, 1995 discloses equipment used in a plasma-assisted chemical vapor deposition for forming a DLC coating onto a breast implants or catheters made of polymeric materials such as polyurethane, silicone rubber or latex.
  • Disadvantages associated with existing processes and equipment include the wear and deterioration of the carbon film over time, non-uniformities in the processed article and low productivity.
  • film deposition processes there exists an inherent risk of separation or peeling off of the film from the target under the perennial stress exerted on a working heart valve by alternating oscillations.
  • titanium-based medical devices with low thrombogeneticity continue to be needed.
  • the invention generally relates to processing multiple targets and is particularly useful in carbon doping of titanium-based medical devices such as components for artificial heart valves.
  • the invention is directed to a vacuum chamber for processing multiple targets.
  • the vacuum chamber which can be part of an ion implantation apparatus, includes a plurality of rotatable holders, mounted on a rotatable disk in an arrangement in which only one work piece is in the beam pathway defined by an ion beam propagating through the chamber. In specific aspects only one holder is on a diametrical direction.
  • the invention is directed to an ion implantation process which includes propagating an ion beam along an ion beam pathway, rotating a disk having a plurality of holders to bring a target supported by a holder in the ion beam pathway and rotating the holder to expose different surfaces of the target to the ion beam.
  • the target supported the holder does not block exposure of another target to the ion beam. For example, only one holder is on a diametrical direction.
  • a target can be moved by a method which includes rotating a disk around a disk rotational axis to impart a first movement component to a target supported by a holder mounted on the disk; and spinning the holder around a holder rotational axis to impart a second movement component to the target.
  • the target is tilted with respect to the disk rotational axis, to the holder rotational axis and with respect to an ion beam pathway.
  • the invention also relates to a carbon doped annulus for an artificial heart valve having a doping uniformity at its surface of about +/- 5 percent (%).
  • an annulus for an artificial heart valve is characterized by a carbon doped surface layer made by ion implantation.
  • the carbon doped layer forms a strong bond with the material of the annulus and becomes integral with the annulus.
  • the boundary between the carbon containing layer and the material of the annulus, such as titanium, is disposed at varying depth inside the annulus.
  • the present process of forming such a layer offers a substantial advantage over the process of depositing films on the surface of a target and reduces or eliminates the inherent risk of peeling off of the film from the target under the stress exerted on a working heart valve by alternating oscillations.
  • the invention also is useful in reducing or minimizing the thrombogeneticity of titanium-based devices, as well as improving the surface properties of other types of solid articles.
  • Carbon doping increases the durability and performance of the annulus for artificial heart valves by reducing friction between annulus and leaflets of the heart valve.
  • the process and apparatus of the invention are designed to avoid uneven processing, such as can result from blocking one work piece with another during irradiation with an ion beam.
  • practicing the invention results in uniform doping and translates in longer lasting surface properties.
  • Medical devices manufactured using the invention have improved wear resistance and, when implanted in a patient, present less risk, requiring replacing with less frequency.
  • the ability to process multiple work pieces at one time translates in manufacturing operations that have increased productivity and efficiency.
  • the target is tilted with respect to the ion beam and rotational axes, facilitating the doping of both interior and exterior surfaces.
  • FIG. 1 is a diagram showing an ion implantation apparatus which includes a chamber suitable for processing multiple work pieces.
  • FIG. 2 is a cross sectional view of an ion collector that can be used to detect charged particles in practicing the invention.
  • FIG. 3 is a top view of a process chamber housing a disk with an odd number of holders arranged around its periphery.
  • FIG. 4 is a cross sectional view of a process chamber that can be used in the ion implantation apparatus shown in FIG. 1.
  • FIG. 5 is a side view of a holder employed to secure a work piece during processing.
  • FIG. 6 is a schematic diagram showing the doping of an annulus for an artificial heart valve in two positions.
  • FIG. 7 A and FIG. 7B are cross sectional views of an annulus placed in a casing prior to being processed, with the casing being shown in a closed position in FIG. 7A and in an open position in FIG. 7B.
  • FIG. 8 A and FIG. 8B illustrate the placement of annulus work pieces in a container, right before processing.
  • FIG. 9A, FIG. 9B and FIG. 9C are illustrations of loading an annulus work piece into a carrier for processing by ion implantation.
  • FIG. 9D is a cross sectional view of an annulus held by a carrier.
  • FIG. 10 is a curve obtained on a CAMECA IMS4F instrument and showing the distribution of carbon in a surface layer of carbon doped titanium after an ion implantation process conducted according to the present invention.
  • the invention generally relates to processing a work piece, also referred to herein as "target”.
  • the invention relates to implanting ions of one material into a solid target made of a different material, thereby modifying its properties. Ion implantation, also referred to as “doping", changes the chemical composition and disrupts the crystal structure of the work piece. Generally, these modifications take place at or near the target surface.
  • the invention can be practiced with titanium-based articles, e.g., articles fabricated from titanium or from titanium-based alloys.
  • work pieces include medical, also referred to as "biomedical” devices, for instance, artificial heart components, e.g., the annulus or casing for artificial heart valves, catheters, implants, dental implants, stents, orthopedic prosthetics devices, medical instruments and, in particular, surgical instruments and others.
  • medical also referred to as "biomedical” devices
  • artificial heart components e.g., the annulus or casing for artificial heart valves, catheters, implants, dental implants, stents, orthopedic prosthetics devices, medical instruments and, in particular, surgical instruments and others.
  • the work piece processed is an annulus for a three leaflet heart valve such as described in RU 2006110832, filed on April 4, 2006, the teachings of which are incorporated herein by reference in their entirety; and in PCT Application having the title "Heart Valve Prosthesis” and filed concurrently herewith under Attorney Docket No. 105.3WO, the teachings of which are incorporated herein by reference in their entirety.
  • the interior surface of the annulus disclosed in the two applications can have ledges, for instance, three larger and three smaller ledges that are present at the upper region of the annulus. Each of the larger ledges is provided with two sockets for mounting a leaflet.
  • the ledges at the upper section of the annulus can be formed by three pairs of intersecting cylindrical surfaces.
  • ions from an ion source are electrostatically accelerated to impinge onto the work piece, thereby doping its surface region with a foreign material, hi a specific example of the invention, the ions are carbon ions, preferably positive carbon ions (C + 12 .
  • ion energies used in ion implantation are within the range of from about 10 kiloelectron volts (keV) to about 500 keV.
  • the invention also can be practiced using lower ion energies, e.g. from about 1 keV to about 10 keV, as well as energies higher than about 500 keV.
  • processes that use low ion energies are known as "ion deposition" processes.
  • the actual amount of ions implanted in the target is the integral of ion current over time. Often, this amount is referred to as the "dose”.
  • the depth of penetration of ions into the target can depend on factors such as the energy of the ions, their nature, and the nature of the target material.
  • the average penetration depth also known as the "range of the ions” is within the range of from about 10 nanometers (nm) to about 1 micrometer or micron ( ⁇ m).
  • the present invention is particularly useful in processing multiple, i.e., at least two, work pieces during a single doping operation or session.
  • the term "session” refers to processing one batch of work pieces without loading fresh pieces or unloading finished product.
  • at least fifteen (15) annulus components for artificial heart valves are processed in one session.
  • any number of work pieces can be processed during a session, it is often practical to process no fewer than 15 work pieces at once.
  • FIG. 1 An apparatus for implanting ions in more than one work piece is shown in FIG. 1. Shown in FIG. 1 is apparatus 10, which includes ion source 12, mass separator 14, ion beam former 16 and process chamber 18.
  • Apparatus 10 can be fabricated from any suitable material or combination of materials, as known in the art. For processing a titanium-based target, for instance, constructing apparatus 10 from titanium or titanium-based alloys prevents or inhibits the generation of foreign particles during processing. Similarly, for carbonic ion implantation, graphite surfaces are preferred within the interior of apparatus 10, to reduce or minimize the
  • interior surfaces of apparatus 10 can be lined or revetted with graphite or can be coated with a graphite film by vapor deposition or other suitable techniques.
  • a vacuum, and in particular a high or ultra high vacuum maintained in apparatus 10 during operation helps to prevent or minimize ion-molecule collisions and resulting charge losses
  • Equipment e.g., pumps, flanges, seals, leak detectors, pressure controls and so forth, that can be used to generate and maintain a desired vacuum in apparatus 10, are known in the art.
  • Apparatus 10, or parts thereof can be externally cooled, for instance by circulating cold water, refrigerants, cryogenically or by other technique known in the art.
  • Ion source 12 is a device capable of producing ions.
  • One type uses electrons emitted by a cathode to ionize a source material. During ionization, electrons are stripped from or added to a neutral atom or molecule to form a charged particle or ion.
  • suitable ion sources include flash or arc chambers. Arc chambers also are referred to as plasma chambers.
  • source materials also referred to as "precursors" include carbonaceous materials such as, for instance, CO 2 and others.
  • one or more electrodes are used to extract ions from ion source 12 through an extraction grid or another type of outlet.
  • Mass separator 14 typically includes one or more magnets. In mass separator 14 ions are deflected by the magnetic field and separated by their mass to charge ratio.
  • Ion beam former 16 includes a mass resolving aperture or another suitable filtering device for selecting an ion beam having the desired properties, for instance the desired mass to charge ratio. Ion beam former 16 also can include beam lenses and other devices known in the art. Preferably, the ion beam is collimated to dimensions suitable for processing a desired target or targets. [0052] From ion beam former 16, the selected ion beam enters process chamber 18 through ion beam inlet 20, for instance an opening or slit preferably sized to allow the propagation of the beam into process chamber 18 and taking into consideration the dimensions of the targets being processed.
  • the ion implantation process was characterized by the following parameters:
  • - implantation dosage no less than about 3x10 18 ion/cm "2 .
  • the ion implantation process it is possible to implement the ion implantation process at different ranges of currents of the C + 12 ion beam. In selecting a suitable current, it can be kept in mind that the effectiveness of the implantation depends on the magnitude of the current. Therefore, the implantation process at low currents is not the most effective. On the other hand, to preserve the physical and mechanical properties of the annuli and effective diffusive penetration of the implanting ions into the annuli, the maximum temperature of the annuli preferably can be around 400°C.
  • the temperature of the annuli is increased by the ions that hit the surface of the annuli and which dissipate their energy into the annuli, therefore, heating the annuli and increasing the process of thermal diffusion of the ions into the annuli.
  • the energy of the carbon ions, as well as the effect of the heating, determine the depth of highest concentration of carbon in the material of the annuli.
  • the thermal threshold at which the material of the annuli loses its desired elastic properties also has been taken into account.
  • Several devices can be employed to detect charged particles in process chamber 18.
  • intercepted ions are detected by measuring current, e.g., by an ammeter, in a conducting lead, or voltage across a resistor from the conducting lead to ground. Voltage differentials can be measured by a voltmeter or viewed on an oscilloscope.
  • Other ion detection arrangements known in the art such as, for instance the one disclosed in U.S. Patent No. 4,517,465, issued on May 14, 1985 to Gault et al. also can be employed.
  • ion collector 22 A specific example of an ion collector that can be used to intercept and detect ions in process chamber 18 is ion collector 22, further described with respect to FIG. 2.
  • ion collector 22 includes hollow cylinder 24, preferably fabricated from or lined with graphite, which is mounted at wall 26 of process chamber 18, not shown in FIG. 2.
  • Face 28 of hollow cylinder 24 is open towards ion beam 30, which propagates through the process chamber from the direction of the ion beam inlet, not shown in FIG. 2.
  • Hollow cylinder 24 also has face 32 which is closed and preferably cone shaped. At least a portion of face 32 is in contact with base 34 which is cooled, for instance, by circulating water.
  • Process chamber 18, used for implanting ions preferably is capable of maintaining a vacuum, e.g., a high or ultrahigh vacuum.
  • Process chamber 18 can be cylindrical or can have another suitable shape, such as, for instance, that of a sphere, hemisphere, prism, parallelepiped or cube. Other shapes, including irregular shapes also can be used.
  • Process chamber can be constructed from a suitable material, e.g., titanium or titanium-based alloys or other materials, as known in the art.
  • Graphite inner surfaces are preferred in the case of carbonic ion implantation processes.
  • process chamber 18 houses a platform such as, for instance a carousel including disk 40.
  • disk 40 is rotatable and has circular shape.
  • Disk 40 also can be constructed in other shapes, such as annular, elliptical, polygonal, e.g., hexagonal, irregular and so forth.
  • the platform also includes a plurality, i.e., at least two, holders 42, each of which can support one or more work pieces. Preferred arrangements of holders 42 on disk 40 are further described below.
  • process chamber 18 Shown in FIG. 3 is process chamber 18 having ion beam inlet 20, ion collector 22 and housing a platform which includes disk 40.
  • Disk 40 is provided with an odd number of evenly spaced holders 42a, arranged along its periphery.
  • ion beam 30 propagates along diametrical direction 44, from ion beam inlet 20 towards ion collector 22, only the work piece or pieces supported by a single holder, for instance, the holder nearest ion beam inlet 20, can be brought in the direct pathway of the ion beam.
  • the ion beam "sees" only work piece(s) supported by this holder and no shadows are cast on other work pieces.
  • This arrangement fulfills the condition of having no more than one holder is in the diametrical direction.
  • the "diametrical direction" or “diametrical line” is the same as or parallel to, in the vertical plane, e.g., above or underneath, the pathway traveled by the ion beam propagating through the process chamber.
  • an even number of holders were to be evenly spaced around the periphery of disk 40, two holders would in the diametrical direction hence a work piece supported by one would block or eclipse another work piece, resulting in uneven processing.
  • the holders are arranged so that the condition of "having in the beam pathway no more than one work piece" is fulfilled.
  • this condition also can be met by adjusting the height at which the work pieces are held during processing.
  • an even number of holders, evenly spaced around the periphery of disk 40 can be employed, with every other holder, e.g., holders 42a, being elevated to a first height and the remaining interspersed holders, e.g., holders 42b, being elevated to a second height.
  • Mechanisms for adjusting the height of a holder in a vacuum chamber can be controlled remotely, manually or in an automated fashion. Examples include vertically translatable arms, lifts, e.g., screw mechanisms, and so forth.
  • the work pieces held by all holders except one can be bent out of the path of the ion beam in a manner which fulfills the condition of having "no more than the work piece or pieces held by a single holder in the beam pathway".
  • the number of holders on disk 40 can depend on the size of the disk, the type of work pieces being processed, the time required for a desired doping and by other factors. In one example for processing heart valve annulus type of work pieces, the number of holders on disk is at least 15.
  • process chamber 18 includes ion beam inlet 20 for receiving ion beam 30 and ion collector 22.
  • process chamber 18 is equipped with one or more devices for sensing and/or controlling the chamber temperature, for instance sensor-controller 52, which helps detect and regulate processing conditions and is particularly useful for achieving desired results during long doping operations requiring temperature modifications, e.g., a significant temperature increase. Mountings in which sensor-controller 52 is not in direct contact with the work piece are preferred.
  • Platform 50 includes disk 40 rotated by shaft 54, powered by motor 56. hi the embodiment illustrated in FIG. 4, motor 56 is placed outside process chamber 18, e.g., underneath bottom wall 58. In other embodiments, a motor or engine driving the rotation of disk 40 can be placed within process chamber 18. Any technique for rotating disk 40 can be used, although the preferred technique is the one described herein.
  • Disk 40 can be rotated at constant or nearly constant velocity and the velocity can be selected based on factors such as target dimensions, target material, type of ions used, desired level of doping and so forth. Disk 40 also can be rotated at variable speeds, to allow each target or region thereof a desired exposure time. For instance, disk 40 can be rotated in step-wise fashion, to expose a holder to the ion beam and to maintain it stationary for a suitable processing time interval.
  • Disk 40 is provided with holders 42, which can be rod-like or can have another suitable shape.
  • holders 42 are perpendicular with respect to disk 40.
  • the upper region of each holder 42 can have one or more supports 60, for engaging or securing a work piece.
  • the number of supports, their shape, dimensions, flexibility, specific means for engaging the work piece and other characteristics can depend on the type of target being processed.
  • supports 60 can be rods, claws, prongs, strips or can have another suitable shape. Slanted as well as un-slanted supports can be used, hi one example, supports 60 open upwardly at an angle suitable for securing the work piece.
  • supports engaging a single target can be the same or different with respect to size, shape, angle at which each is slanted in relation to holder 42 or other characteristics.
  • Supports 60 can be detachable for easy changeovers from one type of target to another or integrated with holder 42. Unattached ends 62 of supports 60 can be designed to allow easy insertion of the work piece, with a spring- or snap-back action for a tight hold during processing.
  • supports 60 impart a tilt to the target that they secure.
  • all supports 60 engaging a single work piece can be tilted with respect to the vertical axis of holder 42.
  • the dimensions and/or shapes of the supports are selected to result in an overall tilt of the work piece that they engage. It is also possible to impart a tilt to a work piece using a single support 60.
  • Holders 42 can be designed to support more than one type of target. Furthermore, a single holder can be designed to support more than one work piece at the same time.
  • each holder 42 can rotate individually, around a rotation axis which is different from the axis of rotation of disk 40.
  • each holder 42 can spin around a vertical axis through the center of the holder.
  • holders 42 can be connected to shaft 54 by frictional, tooth or by another suitable type of gear so that the holders also are rotated by the motor 56. Independent means for rotating holders 42 also can be provided.
  • FIG. 5 A preferred example of a holder mounting is illustrated by FIG. 5. Shown in FIG. 5 is holder 42, including supports 60 slanted at an angle ⁇ with respect to a vertical axis of rotation. Holder 42 has holder body 64, mounted in bearing 66, which is located within disk 40.
  • Roller 68 is provided at bottom end 70 of holder 42.
  • roller 68 is wide and thin with respect to the overall dimensions of holder 42.
  • Roller 68 rests or otherwise engages with ring 72, placed in a gap formed between disk 40 and bottom wall 58 of the process chamber.
  • Ring 72 can be smooth for frictional adhesion or can have teeth for a tooth type connection with a corresponding gear wheel.
  • Operational parameters such as rotation speeds, duration of doping, chamber temperature and others processing conditions can be determined experimentally and can depend on factors such as desired doping level, ion beam characteristics, target material, target geometry and so forth.
  • each work piece in a group of work pieces loaded for processing on holders such as described above preferably has a complex overall movement within the process chamber. For instance, a work piece rotates with disk 40 at a first velocity and with holder 42 at a second velocity. Further complexity is added to the motion of the work piece if it is tilted with respect to holder body 64.
  • a holder has three supports designed to engage and impart a tilt to an annulus for an artificial hear valve. Since annulus 80 resembles a hollow cylinder or a short tube, a preferred angle ⁇ for mounting annulus 80 with respect to the axis of rotation of holder 42 is about 45°. Other tilt angles can be employed.
  • a complex motion of annulus 80 for an artificial heart valve is achieved by a slow rotation imparted by the rotation of disk 40, a fast rotation component due to rotation of holder 42 and the tilt of the annulus with respect to both the rotation axes and the direction of ion beam 30.
  • annulus 80 Shown in FIG. 6 are two extreme positions in the rotation of annulus 80.
  • annulus 80 can be mounted using three supports 60, preferably slanted, on a rotatable holder.
  • annulus 80 In relation to its exposure to ion beam 30, annulus 80 has surfaces A and B.
  • surfaces A shown in thick or bolded lines, are the ones being exposed to ion beam 30 and doped, while surfaces B are "in shadow" and not being processed.
  • surfaces B shown in thick or bolded lines, that are exposed and being doped by ion beam 30, while previously doped surfaces A are now "in shadow".
  • FIG. 7A and FIG 7B illustrate handling of the work pieces, e.g., annuli, before subjecting them to ion implantation.
  • Cleaned and inspected annulus 100 is placed in case 102.
  • case 102 Preferably, a single annulus is placed in one case.
  • the surface of the annulus preferably is supported and makes contact with the case only at clean film 104, e.g., a polyfluorocarbon film, deposited on top of a soft material, for instance, foam rubber 106.
  • clean film 104 e.g., a polyfluorocarbon film, deposited on top of a soft material, for instance, foam rubber 106.
  • Case 102 preferably is constructed in such a way that any change in its position or special orientation, for example, during transportation, does not change the position of the annulus inside the case.
  • the case can be hermetically closed, shown schematically in FIG. 7A, during transportation and storage to prevent dirt and dust from getting inside the casing.
  • the annuli or other work pieces can be stored in the case before being placed in the vacuum chamber for carbon ion implantation treatment.
  • annuli 100 are loaded into containers 108, only one container being shown in FIG. 8A and FIG. 8B.
  • Each container 108 could be cylindrically shaped and made of polyfluorocarbon or another suitable material.
  • Container 108 can be hermetically closed with a lid to prevent contamination of the annuli.
  • holder 110 is mounted on device 112. Disposed on holder 110 are supports for securing work pieces to be processed, specifically carriers 114.
  • Carriers 114 preferably are made of titanium wire and are formed so that a carrier's round portion tightly encircles the groove of the annulus along plane B shown in Fig. 7B.
  • Holder 110 is then positioned in such a way that one of carriers 114 is positioned coplanar with Plane B shown in Fig. 7B, nearby the open case 102 also shown in FIG. 7B.
  • one of the arms of carrier 114 is then opened, as illustrated, so that the carrier encompasses the annulus in Plane B, shown in FIG. 7B, without contacting the annulus.
  • open arm 116 of carrier 114 is released as shown in the position illustrated in FIG. 9B until the internal surface of carrier 114 contacts annulus 100 along its groove as shown in FIG. 9C.
  • carrier 114 touches no other surface of the annulus 100, as shown in FIG. 9D which is a cross sectional view along the A-A direction of annulus 100 held by carrier 114.
  • Remaining annuli can be mounted on holders 110 with the help of carriers 114 in a similar fashion.
  • container 108 is hermetically closed. Annuli in the container are ready for transport to the place of ion implantation without the annuli getting in contact with any surface other that the surface of the carrier during transportation.
  • holder 110 supporting carriers 114, is disconnected from device 112. Holder 110 is then transported to the vacuum chamber and is mounted onto a device similar to device 112 for holding holder 110 in the chamber. After all the annuli are loaded, the chamber, it is sealed an evacuated to reach a desired vacuum for ion implantation.
  • a processed work piece preferably has a doped surface as determined by one of the above-described analytical technique such as, for instance by the SIMS on a CAMECA IMS4F instrument, as shown in Fig. 10.
  • the curve presented in Fig. 10 shows the distribution of carbon in a surface layer of carbon doped titanium after an ion implantation process conducted according to the present invention. At the depth up to 0.2 ⁇ the concentration of carbon is approximately constant. The region between about 0.2 ⁇ and 0.22 ⁇ has the highest the carbon concentration. The depth of ion penetration in this region is a function of the energy of the ions selected for the implantation process. At lower energies the highest carbon concentration region will shift to the left of the curve in Fig.
  • the doping uniformity observed at the surface of a titanium heart valve annulus is about ⁇ 5 %.

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  • Public Health (AREA)
  • General Health & Medical Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Metallurgy (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Surgery (AREA)
  • Vascular Medicine (AREA)
  • Dermatology (AREA)
  • Medicinal Chemistry (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Transplantation (AREA)
  • Physical Vapour Deposition (AREA)

Abstract

Chambre destinée au traitement de cibles multiples, qui comporte une pluralité d'éléments de retenue rotatifs, montés sur un disque rotatif, un seul élément de retenue se trouvant dans une direction diamétrale, spécifiquement dans une direction qui est la même que celle du faisceau ionique ou verticalement parallèle à ce dernier. Un procédé d'implantation d'ions consiste à propager un faisceau ionique le long d'une trajectoire de faisceau ionique, à faire tourner un disque pourvu d'une pluralité d'éléments de retenue pour amener une cible portée par un élément de retenue dans la trajectoire du faisceau ionique et à faire tourner l'élément de retenue pour exposer différentes surfaces de la cible au faisceau ionique. Dans ce procédé, un seul élément de retenue se trouve dans la direction diamétrale. Un procédé permettant de déplacer une cible pendant l'implantation d'ions est également décrit. La présente invention est particulièrement utile pour doper des dispositifs médicaux à base de titane avec des ions de carbone.
PCT/IB2006/001060 2005-04-29 2006-04-28 Equipement et procede de traitement par implantation d'ions de dispositifs medicaux WO2006117625A2 (fr)

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US60/676,148 2005-04-29

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2962138A1 (fr) * 2010-07-02 2012-01-06 Valois Sas Procede de traitement de surface d'un dispositif de distribution de produit fluide.
WO2012001330A3 (fr) * 2010-07-02 2012-03-29 Valois Sas Procede de traitement de surface d'un dispositif de distribution de produit fluide.

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US4693760A (en) * 1986-05-12 1987-09-15 Spire Corporation Ion implanation of titanium workpieces without surface discoloration
US5383934A (en) * 1992-03-04 1995-01-24 Implant Sciences, Corporation Method for ion beam treating orthopaedic implant components
US5674293A (en) * 1996-01-19 1997-10-07 Implant Sciences Corp. Coated orthopaedic implant components
US5855950A (en) * 1996-12-30 1999-01-05 Implant Sciences Corporation Method for growing an alumina surface on orthopaedic implant components
DE19730296A1 (de) * 1997-07-15 1999-01-21 Medic Medizintechnik Lothar Se Verfahren und Vorrichtung zur Steigerung der Hämokompatibilität von Implantaten
US5980974A (en) * 1996-01-19 1999-11-09 Implant Sciences Corporation Coated orthopaedic implant components
WO2002003883A2 (fr) * 2000-07-10 2002-01-17 Epion Corporation Endoprotheses medicales a efficacite amelioree par gcib
US6761736B1 (en) * 1999-11-10 2004-07-13 St. Jude Medical, Inc. Medical article with a diamond-like carbon coated polymer

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Publication number Priority date Publication date Assignee Title
US4693760A (en) * 1986-05-12 1987-09-15 Spire Corporation Ion implanation of titanium workpieces without surface discoloration
US5383934A (en) * 1992-03-04 1995-01-24 Implant Sciences, Corporation Method for ion beam treating orthopaedic implant components
US5674293A (en) * 1996-01-19 1997-10-07 Implant Sciences Corp. Coated orthopaedic implant components
US5980974A (en) * 1996-01-19 1999-11-09 Implant Sciences Corporation Coated orthopaedic implant components
US5855950A (en) * 1996-12-30 1999-01-05 Implant Sciences Corporation Method for growing an alumina surface on orthopaedic implant components
DE19730296A1 (de) * 1997-07-15 1999-01-21 Medic Medizintechnik Lothar Se Verfahren und Vorrichtung zur Steigerung der Hämokompatibilität von Implantaten
US6761736B1 (en) * 1999-11-10 2004-07-13 St. Jude Medical, Inc. Medical article with a diamond-like carbon coated polymer
WO2002003883A2 (fr) * 2000-07-10 2002-01-17 Epion Corporation Endoprotheses medicales a efficacite amelioree par gcib

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2962138A1 (fr) * 2010-07-02 2012-01-06 Valois Sas Procede de traitement de surface d'un dispositif de distribution de produit fluide.
WO2012001330A3 (fr) * 2010-07-02 2012-03-29 Valois Sas Procede de traitement de surface d'un dispositif de distribution de produit fluide.

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