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WO2008112888A1 - Dispositif et procédé de fabrication d'un filtre à particules comportant des micropores espacés régulièrement - Google Patents

Dispositif et procédé de fabrication d'un filtre à particules comportant des micropores espacés régulièrement Download PDF

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Publication number
WO2008112888A1
WO2008112888A1 PCT/US2008/056848 US2008056848W WO2008112888A1 WO 2008112888 A1 WO2008112888 A1 WO 2008112888A1 US 2008056848 W US2008056848 W US 2008056848W WO 2008112888 A1 WO2008112888 A1 WO 2008112888A1
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WO
WIPO (PCT)
Prior art keywords
membrane
membrane substrate
substrate
mask
exposure device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2008/056848
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English (en)
Inventor
John C. Wolfe
Paul Ruchhoeft
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University of Houston
Original Assignee
University of Houston
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US11/856,615 external-priority patent/US7960708B2/en
Application filed by University of Houston filed Critical University of Houston
Priority to JP2009553778A priority Critical patent/JP2010521291A/ja
Priority to US12/530,978 priority patent/US8987688B2/en
Priority to EP08743851A priority patent/EP2126629A4/fr
Publication of WO2008112888A1 publication Critical patent/WO2008112888A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0002—Organic membrane manufacture
    • B01D67/0023—Organic membrane manufacture by inducing porosity into non porous precursor membranes
    • B01D67/0032—Organic membrane manufacture by inducing porosity into non porous precursor membranes by elimination of segments of the precursor, e.g. nucleation-track membranes, lithography or laser methods
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0002—Organic membrane manufacture
    • B01D67/0023—Organic membrane manufacture by inducing porosity into non porous precursor membranes
    • B01D67/0032—Organic membrane manufacture by inducing porosity into non porous precursor membranes by elimination of segments of the precursor, e.g. nucleation-track membranes, lithography or laser methods
    • B01D67/0034—Organic membrane manufacture by inducing porosity into non porous precursor membranes by elimination of segments of the precursor, e.g. nucleation-track membranes, lithography or laser methods by micromachining techniques, e.g. using masking and etching steps, photolithography
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/48—Polyesters
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/12—Production of screen printing forms or similar printing forms, e.g. stencils
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/20—Exposure; Apparatus therefor
    • G03F7/2037—Exposure with X-ray radiation or corpuscular radiation, through a mask with a pattern opaque to that radiation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
    • H01J37/305—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching
    • H01J37/3053—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching for evaporating or etching
    • H01J37/3056—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching for evaporating or etching for microworking, e. g. etching of gratings or trimming of electrical components
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2323/00—Details relating to membrane preparation
    • B01D2323/42—Details of membrane preparation apparatus
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/02—Details relating to pores or porosity of the membranes
    • B01D2325/028—Microfluidic pore structures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/30—Electron or ion beam tubes for processing objects
    • H01J2237/317—Processing objects on a microscale
    • H01J2237/3174—Etching microareas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/30—Electron or ion beam tubes for processing objects
    • H01J2237/317—Processing objects on a microscale
    • H01J2237/3175—Lithography
    • H01J2237/31752—Lithography using particular beams or near-field effects, e.g. STM-like techniques
    • H01J2237/31755—Lithography using particular beams or near-field effects, e.g. STM-like techniques using ion beams
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/30—Electron or ion beam tubes for processing objects
    • H01J2237/317—Processing objects on a microscale
    • H01J2237/3175—Lithography
    • H01J2237/31777—Lithography by projection
    • H01J2237/31788—Lithography by projection through mask

Definitions

  • TITLE Device and method for manufacturing a particulate filter with regularly spaced micropores
  • the present invention relates to a method for manufacturing a particulate filter comprising a membrane with a high density array of regularly spaced micropores and a macroporous support.
  • a lithographic apparatus or device is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate, such as a membrane substrate.
  • a lithographic device can be used, for example, in the manufacture of integrated circuits (ICs).
  • a patterning device which is alternatively referred to as a mask or a reticle, may be used to generate a circuit pattern to be formed on an individual layer of the IC.
  • This pattern can be transferred onto a target portion (e.g. comprising part of, one, or several dies) on a substrate (e.g. a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate.
  • resist radiation-sensitive material
  • a single substrate will contain a network of adjacent target portions that are successively patterned.
  • lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at one time, and so-called scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the " scanning" - direction) while synchronously scanning the substrate parallel or anti-parallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.
  • the formation of membrane filters with small straight-through holes of extremely small diameter and methods of making such porous bodies and/or microporous membranes are well known.
  • Microporous membranes can be produced with particles which produce chains of defects in the glass, crystal or polymer membrane corresponding to the path of the particles. These defects make the areas around them very sensitive to various chemical agents. An exposure of relatively short duration to these agents makes it possible to produce pores at various locations. A longer exposure makes it possible to expand the number of pores. Accordingly, in various prior art processes the duration of chemical attack or etching facilitates control of the diameter of the pores produced, i.e. the filtration characteristic of the filter.
  • Various methods including combinations of irradiation damage along substantially straight paths and chemical removal of the damaged material to provide pores or holes; bombarding a solid with heavy energetic particles to produce tracks of radiation damaged material which are removed by etching; forming ionization tracks in a membrane and removing by exposure to a suitable etchant solution; two-step etching processes that permits widening of the ion tracks to make a range of larger pore sizes; and/or the like.
  • the pores have been constructed to have a conical shape so as to assist back flushing.
  • Various embodiments of the present invention generally relate to lithographic exposure devices for fabricating a microporous filter membrane comprising means for exposing a membrane substrate to a beam comprising at least one energetic particle; means for conveying said membrane substrate; and, a mask positioned between said membrane substrate and at least one source of said at least one energetic particle, said beam comprising at least one particle transmitted through said mask.
  • Still further embodiments comprise a process for fabricating a microporous membrane filter, said process comprising the steps of applying an intermediate mask layer and a resist coating to a membrane substrate; conveying said membrane substrate in a stepwise fashion adjacent a mask; exposing said resist coating with at least one beam comprising at least one energetic particle emitted from at least one radiation source directed at least partially through said mask; developing said resist coating; etching said resists' pattern through said intermediate mask layer; and, etching said intermediate mask layer's pattern into said membrane substrate.
  • Figure 1 is an illustration of an embodiment of the present invention wherein a beam of energetic particles impinges on a substantially planar mask perforated by openings damaging a non-planar membrane substrate in a highly uniform array of regularly spaced regions.
  • Figure 2 is an illustration of a membrane substrate subjected to a beam of energetic particles according to the embodiment of Figure 1 after development in a suitable solvent.
  • Figure 3 is an illustration of an embodiment of the present invention where a high emissivity coating is applied to the membrane to enhance radiative cooling during energetic particle exposure.
  • Figure 4 is an illustration of a shadow generated with a point source of particles.
  • Figure 5 is an illustration a shadow generated with particles emanating from different points on a source.
  • Figure 6 is an illustration of an embodiment of electrostatic clamping for inhibiting substrate motion during ion exposure.
  • Figure 7 is an illustration of an embodiment of a reel-to-reel apparatus for manufacturing microporous filters.
  • Figure 8 is an illustration of an etch depth in a Mylar membrane filter, developed in a hot 20% K0H/H 2 0 solution, as a function of 50 keV He+ ion dose.
  • Figure 9 is an illustration of He + ion trajectories in a Mylar membrane filter for an initial energy of 50 keV.
  • Figure 10 is an illustration of H + ion trajectories in a Mylar membrane filter for initial energies of a) 400 keV, b) 600 keV, and c) 900 keV.
  • Figure 11 is a scanning electron micrograph of a) stencil mask for fabricating a particulate filters with 0.8 ⁇ m stencil openings and b) a textured polyester (Mylar) film printed with 50 keV helium ions and developed in a hot 20% KOH/H2O solution. The film was loosely attached to a platen at the corners with tape during the exposure. The flatness of the film was about 2 mm.
  • the term "radiation” means and refers to energy radiated or transmitted as rays, waves, in the form of particles.
  • various embodiments of the present invention provides processes and systems for manufacturing large area or enhanced area filter membranes from polymeric sheet stock. Further, various embodiments of the present invention relate to the as produced filter membranes.
  • Embodiments of processes, systems and filters of the present invention generally provide for at least one of minimized process variation and cost through producing the filter membranes in a continuous process; producing filter membranes with increased and/or enhanced pore density without pore overlap; producing filter membranes without the necessity of a solid support; producing large area filters without the necessity of splicing or tiling small discrete filters together, and/or the like.
  • energetic particles are used to damage a polymeric membrane substrate and a suitable etchant, such as, but not limited to a hot solution of KOH, is used to remove the damaged substrate material.
  • a suitable etchant such as, but not limited to a hot solution of KOH.
  • a substantially uniform array of holes is formed by energetic particle exposure through a mask. In an embodiment, the array of holes is uniform throughout the substrate material.
  • Membrane substrates of the present invention can be produced supported or unsupported.
  • a membrane substrate is processed as a free-standing polymeric sheet.
  • a macroporous backing is present on at least a portion of the substrate to enhance strength characteristics.
  • a membrane substrate is deposited by extrusion, casting, spin coating, vapor deposition, epitaxy, chemical vapor deposition, sputtering, and/or any other process common in the art.
  • Typical thicknesses of a membrane substrate of the present invention in an embodiment are about 20 ⁇ m to about 500 nm.
  • a thicknesses of a membrane substrate of the present invention is about 100 nm to about 5 ⁇ m.
  • a thicknesses of a membrane substrate of the present invention is about 10 nm to about 10 ⁇ m.
  • a thicknesses of a membrane substrate of the present invention is about 5 nm to about 15 ⁇ m.
  • various embodiments of the membranes of the present invention can be formed of any thickness.
  • Deposition techniques are well understood in the art field, especially the semiconductor art field, and the production of substantially flat membrane substrate, void from any substantial protrusions or other irregularities, is readily obtainable. However, in applications where a substantially flat membrane substrate is not required, extrusion, casting, spraying, sol-gel plating, and/or the like is capable of use for forming the membrane substrate. In general, any technique known in the art can be used in various embodiments of the present invention.
  • a membrane filter of various embodiments of the present invention is characterized in that said membrane comprises a substantially flat layer of substantially uniform thickness and in that the surface of said layer is substantially void of any protrusions or any other irregularities.
  • Appropriate thickness and uniformity of a membrane are characteristics capable of optimization to resist high relative fluxes from a variety of processes.
  • the filter should present a resistance which is as low as possible and therefore, in a preferred embodiment of the invention, comprises a membrane whose thickness is smaller than the average pore size and whose pore density is larger than 1 million per square centimeter.
  • the characteristic of selectivity of a filter membrane is determined by its largest pore(s). Consequently it is desirable to have a pore size distribution which is as uniform as possible.
  • a specific embodiment of the filter according to the invention is characterized in that the pores consist of perforations with relatively smooth edges and in that the membrane features a relatively sharp, well defined pore size distribution within a standard deviation of less than about 5%, as mentioned previously.
  • the standard deviation is less than about 3%.
  • the standard deviation is less than about 1%.
  • a membrane is capable of better performance characteristics with uniformity of hole size.
  • various embodiments are capable of producing a non-uniform hole size as needed for a particular process and/or membrane.
  • the perforations in the membrane may be constructed so as to be cylindrical, tapering, and/or the like. Tapering embodiments are particularly useful in "back flush" applications, clogged perforations are easily reopened by means of a counter pressure pulse.
  • Suitable materials for the membrane filter of various embodiments of the present invention are preferentially of a polymeric material, such as, but not limited to polyurethane, polytetrafluoroethylene (TEFLON), polyamide, polyamide, polyvinyl, polymethylmethacrylate, polypropylene, polyolefm, polycarbonate, polyester, cellulose, polyformaldehyde and polysulfone.
  • a polymeric material such as, but not limited to polyurethane, polytetrafluoroethylene (TEFLON), polyamide, polyamide, polyvinyl, polymethylmethacrylate, polypropylene, polyolefm, polycarbonate, polyester, cellulose, polyformaldehyde and polysulfone.
  • a biocompatible coating such as a heparin coating and/or the like.
  • the support may be macroporous with a tortuous pore structure, a sintered ceramic material, a sintered metal powder or a polymeric tortuous membrane, as well as an initially dense material in which in a later stage openings are made, for example in a semiconductor wafer, a metal support or an inorganic disc.
  • the total strength of a membrane substrate of the present invention may be increased by a number of relatively thin supporting bridges in the support underneath.
  • an intermediate layer may be deposited for bonding enhancement and stress reduction. Bonding enhancement layers might be silicon dioxide and titanium dioxide depending upon the nature of the membrane and support materials.
  • the intermediate layer may moreover act as an etch stop layer.
  • any source of energetic particles such as, ions, photons, electrons, neutral energetic atoms, and/or molecules can be used, such as, but not limited to photons, He + , H + , suitable equivalents, and/or the like.
  • a substantially parallel beam of energetic particles is directed so as to impinge on a substantially planar mask perforated by stencil openings.
  • the stencil contains a series of uniform evenly dispersed holes through the mask.
  • the stencil openings have a particular shape or design. Portions of the energetic particles passing through the holes or stencil openings in the mask damage a membrane substrate positioned about the mask.
  • the membrane substrate is essentially planar.
  • the membrane substrate is non-planar.
  • the substrate After exposing the membrane substrate to the beam of energetic particles, the substrate may be washed in a suitable solvent to remove the damaged portions of the membrane substrate and thereby revealing the holes. Deformation of the membrane substrate during these steps is acceptable, under constraints of the present invention.
  • a deposited masking layer particularly of a material sensitive to energetic particle exposure, is employed as the auxiliary layer which is brought in the desired pattern by means of an energetic particle lithography technique.
  • the masking layer will be in contact with the membrane layer and therefore enables the transfer of its pattern to the membrane layer with a very high degree of precision.
  • an intermediate masking layer may be employed.
  • a membrane filter of the present invention is biocompatible.
  • a characteristic of a biocompatible membrane is that its surface is smooth, with a surface roughness less than the pore size will, thereby inhibiting sticking of particles or cells on the membrane and in the perforations.
  • various embodiments of a biocompatible membrane of the present invention comprises a filter capable of use for cell-cell separation techniques and other medical and bio-medical purposes.
  • the support and the membrane are constituted from equivalent materials with the same or similar components, for example polycarbonate.
  • a filter of this kind is applicable in a wide temperature range, with a good cohesion between the support and the membrane.
  • a membrane of the kind used in the filter according to various embodiments of the invention may itself very well act as a support for an ultrafiltration layer.
  • Very thin ultrafiltration layers typically with a thickness less than 200 nm, may be deposited in or over the perforations of the membrane to constitute an ultrafiltration filter.
  • the thickness of the ultrafiltration layer can varied as is suitable for the particular process.
  • a film processed under an embodiment of the present invention is held essentially stationary while energetic particle exposure is performed.
  • an electrostatic clamp as shown in Figure 5 is used to clamp a thin metal film deposited onto the membrane substrate, thereby holding the membrane substrate essentially stationary with respect to the clamp.
  • exemplary embodiments of the present process may utilize simultaneous or sequential deposition of multiple metals of controlled composition.
  • Other exemplary embodiments may utilize small metal catalyst particles, such as nickel, to grow orderly arrays of precisely positioned carbon nanotubes, for example.
  • the process may also allow for alternating between different gasses, ions, and/or precursors to form multilayer structures.
  • various embodiments of the present invention comprise a lithographic exposure device for fabricating a microporous filter membrane comprising means for exposing a membrane substrate to a beam comprising at least one energetic particle; means for conveying said membrane substrate; and, a mask positioned between said membrane substrate and at least one source of said at least one energetic particle, said beam comprising at least one ion transmitted through said mask.
  • Further embodiments comprise a filter membrane comprising at least one pore with at least one about one micrometer pore.
  • the mask is substantially stationary.
  • a clamp is used to secure said membrane substrate.
  • any source of radiation can be used in various embodiments of the present invention.
  • a helium ion source is used for irradiation.
  • a hydrogen ion source is used for irradiation.
  • any radiation source can be used.
  • a suitable energy level is an energy level sufficient to completely penetrate the membrane substrate.
  • the energy may be adjusted to tailor the specific shape of the micropores in the membrane.
  • the energy is greater than 500 keV.
  • the energy is greater than 300 keV.
  • the energy is greater than 100 keV.
  • the energy is greater than 50 keV.
  • the energy is greater than 25 keV.
  • the energy is greater than 10 keV.
  • any energy level can be used as is appropriate for the particular application.
  • a lithographic exposure device of an embodiment of the present invention comprises a system for conveying the membrane substrate in a stepwise fashion wherein said membrane substrate is advanced about a length of said mask for every step.
  • an etchant system such as hot KOH solution or an organic solvent, is used to remove the damaged membrane substrate.
  • Further embodiments comprise application of a high emissivity coating to said filter membrane substrate prior to exposure.
  • various further embodiments comprise removal of the high emissivity coating from said filter membrane substrate after exposure.
  • An example of a water soluble high emissivity coating is black tempera paint.
  • Most other paints, particularly those incorporating titanium dioxide particles also have high emissivity and can be removed in suitable solvents.
  • Silicones also have high emissivities.
  • the choice of a removable high emissivity coatings depends upon the ability of the membrane to withstand the solvent used to remove the coating. For example, Teflon membranes can tolerate acetone and commercial paint stripping solvents whereas polyester membranes cannot.
  • more than one etching step is performed, such that the film is etched by more than one etchant.
  • a surfactant is capable of being added to the pre-etchant or etchant to improve their wetting characteristics and to lower the cone angle, as is understood by one of ordinary skill in the art.
  • Filters produced with various processes of the present invention are suitable for use in any process or apparatus wherein a separation at least partially based upon size is desired.
  • various embodiments find wide applicability for use in separating materials of a very small size, such as, for example and not by way of limitation, virus, cysts, bacteria and the like.
  • Further industrial embodiments of various membranes produced with processes of the present invention comprise purification of drinking and waste water, pharmaceuticals, food, fuels, chemicals, gas separation ultra filtration filter(s), and/or the like.
  • Various embodiments of the present invention comprise a process for fabricating a membrane filter, said process comprising the steps of conveying a membrane substrate in a stepwise fashion adjacent a mask; damaging said membrane substrate with at least one beam comprising at least one energetic particle emitted from at least one radiation source directed at least partially through said mask; and, removing said damaged membrane substrate with an etchant.
  • Still further embodiments comprise a process for fabricating a microporous membrane filter, said process comprising the steps of applying an intermediate mask layer and a resist coating to a membrane substrate; conveying said membrane substrate in a stepwise fashion adjacent a mask; exposing said resist coating with at least one beam comprising at least one energetic particle emitted from at least one radiation source directed at least partially through said mask; developing said resist coating; etching said resists' pattern through said intermediate mask layer; and, etching said intermediate mask layer's pattern into said membrane substrate.
  • Figure 1 is an illustration of beam (3) of energetic particles impinges on a substantially planar mask (2) perforated by stencil openings (4).
  • a structured beam of transmitted beamlets (5) damages the non-planar membrane substrate (1) in a highly uniform array of regularly spaced regions.
  • Figure 1 illustrates the exposure process in which a substantially parallel beam (3) of energetic particles (ions, electrons, or neutral energetic atoms or molecules) impinges on a substantially planar mask (2) perforated by stencil openings (4).
  • Transmitted beamlets (5) form a structured beam that damages the non-planar membrane substrate (1) in a highly uniform array of regularly spaced regions.
  • Figure 2 shows that after development in a suitable solvent, the non-planar membrane substrate (1) becomes permeated by a highly uniform array of regularly spaced pores (6). The substrate may deform from its original shape during development.
  • Figure 2 is an illustration of a membrane substrate after development in a suitable solvent, the non-planar membrane substrate (1) is permeated by a highly uniform array of regularly spaced pores (6).
  • the coating should be applied to the side that is opposite to the side irradiated by energetic particles.
  • the emissivity of such a coating is about greater than 0.9.
  • the emissivity of such a coating is about greater than 0.8.
  • the emissivity of such a coating is about greater than 0.5.
  • the high emissivity coating should be easily removed after the exposure, preferably during the removal of the damaged regions of the membrane substrate.
  • FIG. 3 is an illustration of the an embodiment of the present invention where a high emissivity coating (7) is applied to the membrane to enhance radiative cooling during energetic particle exposure.
  • the emissivity of the coating is dependent upon its thickness. In a preferred embodiment, the thickness is between 10 and 125 ⁇ m.
  • the dimensions of the transmitted beamlets should be essentially unchanged over the height of the topography.
  • flatness is not expected to be better than 1 mm.
  • most substrates form tension wrinkles, which are corrugations in the machine direction that disappear immediately after relieving tension.
  • Substrates with buckles will usually form much larger tension wrinkles than flat substrates.
  • the peaks of the tension wrinkles could scrape the mask causing it to break.
  • Various embodiments therefore anticipate patterning over a distance of 5-10 mm from the mask. As such, various embodiments are capable of forming an image over such a large depth-of-f ⁇ eld (DoF), defined as the maximum distance over which a particular feature size can be formed, is an important consideration.
  • DoF depth-of-f ⁇ eld
  • a system comprising energetic particle proximity lithography where DoF is limited primarily by the finite size of the energetic particle source, is capable of being used.
  • Figure 4 shows that the edges of an image of a mask 52 on a substrate 51 are sharp and well-defined for a point-source 57 of particles.
  • Figure 5 shows that, for an extended source 60, the edges of the shadow of a mask 62 on a substrate 61 are blurred by the overlapping images created by ions emanating from different points on the source. The width ⁇ of this penumbral blur is approximately equal to the resolution limit in the printed image.
  • ⁇ d ⁇ /L where ⁇ is the diameter of the source, d is the distance from the mask to the substrate, and L is the distance from the source to the mask.
  • DoF can be more than 10,000 times larger than the minimum resolvable feature; thus, 1 micrometer size features can be printed on a surface located 10 mm from the mask. This implies that a freestanding membrane need only be held flat within a 5-10 mm tolerance for creating 1 micrometer pore openings. This is more than 100,000 times less constraining than the 100 nm flatness tolerances discussed by Van Rijn.
  • FIG. 6 is an illustration of an electrostatic clamping concept for preventing substrate motion during ion exposure.
  • a conducting substrate platen 109 is divided by an electrically insulating spacer 112 into two conducting regions 110 and 111.
  • the polymeric membrane material is coated with a thin metal film 113 to make the top surface electrically conducting. Electrostatic forces, generated by voltages applied to conducting regions 110 and 111 then clamp the polymer to the platen.
  • the membrane substrate and the substrate platen 109 is divided by an electrically insulating spacer 112 into two regions 110 and 111.
  • the polymeric membrane material may be coated with a thin metal film 114 to make the top surface electrically conducting and different voltages applied to regions 110 and 111. Electrostatic forces between the platen and the metal film then clamp the polymer to the platen.
  • the flatness of the platen need only conform to the Depth of Field (DoF) specifications.
  • DoF Depth of Field
  • the clamping need not produce a perfectly flat polymeric film. Voids and wrinkles may be tolerated as long as they conformed to the DoF specifications.
  • a reel-to-reel manufacturing apparatus for manufacturing microporous filters in a continuous manner.
  • Polymeric feed stock 210 is fed from a supply reel 213 through a series of in- feed rollers tensioner 214, capstan drive 216, and idler 218 onto the substrate platen 290 where it is exposed to an ion beam 230 through a stencil mask 200. After exposure, the membrane passes through tensioner 217, capstan drive 219, and idler 215 and wound on take-up reel 220.
  • a film processed under an embodiment of the present invention is held stationary while energetic particle exposure is taking place.
  • the polymeric membrane material may be coated with a thin metal film 114 to make the top surface electrically conducting and different voltages applied to regions 110 and 111. Electrostatic forces between the platen and the metal film then clamp the polymer to the platen.
  • the flatness of the platen need only conform to the DoF specifications.
  • the clamping need not produce a perfectly flat polymeric film. Voids and wrinkles may be tolerated as long as they conformed to the DoF specifications.
  • Hydrogen ions are capable of use in this regard.
  • Figure 10 shows that 400 keV, 600 keV, and 900 keV protons have sufficient range to penetrate mylar films of varying thickness, such as, but not limited to, 3, 4, and/or 5 micrometers with a blur of less than 0.1 micrometers.
  • Figure 11 a) A silicon nitride stencil mask with 0.8x1.6 ⁇ m 2 openings.
  • Figure 10 b) is the 50 keV He+ image of the stencil mask in a) printed in a sample of Mylar sheet stock.
  • the Mylar 1x1 in 2 sheet was loosely attached to a holder with tape at the corners.
  • the flatness of the wrinkled sample was estimated at 2 mm.
  • the film was developed in hot KOH (4O 0 C). Although the energy of the helium ions was insufficient to completely penetrate the mylar film, this micrograph clearly demonstrates direct patterning of mylar with helium ions over a large depth of field.

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  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Manufacturing & Machinery (AREA)
  • General Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Analytical Chemistry (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Micromachines (AREA)

Abstract

L'invention concerne, dans divers modes et formes de réalisation, des dispositifs et des procédés permettant de fabriquer des filtres à particules microporeux comportant des pores espacés régulièrement, et dans lesquels des substrats de membrane feuille sont exposés à un rayonnement de particules énergétiques à travers un masque, et les régions endommagées sont éliminées dans un développeur approprié. La profondeur de champ requise est obtenue au moyen de particules énergétiques permettant de réduire au minimum la diffraction, et d'une source de particules énergétiques présentant un diamètre suffisamment faible.
PCT/US2008/056848 2007-03-13 2008-03-13 Dispositif et procédé de fabrication d'un filtre à particules comportant des micropores espacés régulièrement Ceased WO2008112888A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2009553778A JP2010521291A (ja) 2007-03-13 2008-03-13 規則的に間隔をおいて配置されたマイクロ細孔を有する微粒子フィルタを製造するためのデバイスおよび方法
US12/530,978 US8987688B2 (en) 2007-03-13 2008-03-13 Device and method for manufacturing a particulate filter with regularly spaced micropores
EP08743851A EP2126629A4 (fr) 2007-03-13 2008-03-13 Dispositif et procédé de fabrication d'un filtre à particules comportant des micropores espacés régulièrement

Applications Claiming Priority (4)

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US89459307P 2007-03-13 2007-03-13
US60/894,593 2007-03-13
US11/856,615 US7960708B2 (en) 2007-03-13 2007-09-17 Device and method for manufacturing a particulate filter with regularly spaced micropores
US11/856,615 2007-09-17

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WO2008112888A1 true WO2008112888A1 (fr) 2008-09-18

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012146500A1 (fr) * 2011-04-28 2012-11-01 Siemens Aktiengesellschaft Microtamis et procédé de fabrication d'un microtamis
JP2013537469A (ja) * 2010-05-03 2013-10-03 クリーティービー マイクロテック， インク． 高分子マイクロフィルタおよびその製造方法
TWI464843B (zh) * 2011-03-02 2014-12-11 Unimicron Technology Corp 封裝基板
US10576430B2 (en) 2017-12-11 2020-03-03 General Electric Company System and method for manufacturing a membrane filter

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5753014A (en) 1993-11-12 1998-05-19 Van Rijn; Cornelis Johannes Maria Membrane filter and a method of manufacturing the same as well as a membrane
US5786396A (en) * 1996-08-21 1998-07-28 Tonen Chemical Corporation Method of producing microporous polyolefin membrane
US6762396B2 (en) * 1997-05-06 2004-07-13 Thermoceramix, Llc Deposited resistive coatings
US20050128448A1 (en) * 2003-12-10 2005-06-16 Asml Netherlands B.V. Lithographic apparatus and device manufacturing method
US20050263452A1 (en) * 1999-12-08 2005-12-01 Jacobson James D Microporous filter membrane, method of making microporous filter membrane and separator employing microporous filter membranes
US20060124865A1 (en) * 2002-05-20 2006-06-15 Wolfe John C Energetic neutral particle lithographic apparatus and process

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7597815B2 (en) * 2003-05-29 2009-10-06 Dressel Pte. Ltd. Process for producing a porous track membrane
JP2005174590A (ja) * 2003-12-08 2005-06-30 Denso Corp スタータ用電磁スイッチ
DE102004034983A1 (de) * 2004-07-16 2006-02-02 Carl Zeiss Jena Gmbh Lichtrastermikroskop

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5753014A (en) 1993-11-12 1998-05-19 Van Rijn; Cornelis Johannes Maria Membrane filter and a method of manufacturing the same as well as a membrane
US5786396A (en) * 1996-08-21 1998-07-28 Tonen Chemical Corporation Method of producing microporous polyolefin membrane
US6762396B2 (en) * 1997-05-06 2004-07-13 Thermoceramix, Llc Deposited resistive coatings
US20050263452A1 (en) * 1999-12-08 2005-12-01 Jacobson James D Microporous filter membrane, method of making microporous filter membrane and separator employing microporous filter membranes
US20060124865A1 (en) * 2002-05-20 2006-06-15 Wolfe John C Energetic neutral particle lithographic apparatus and process
US20050128448A1 (en) * 2003-12-10 2005-06-16 Asml Netherlands B.V. Lithographic apparatus and device manufacturing method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP2126629A4

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013537469A (ja) * 2010-05-03 2013-10-03 クリーティービー マイクロテック， インク． 高分子マイクロフィルタおよびその製造方法
TWI464843B (zh) * 2011-03-02 2014-12-11 Unimicron Technology Corp 封裝基板
WO2012146500A1 (fr) * 2011-04-28 2012-11-01 Siemens Aktiengesellschaft Microtamis et procédé de fabrication d'un microtamis
US10576430B2 (en) 2017-12-11 2020-03-03 General Electric Company System and method for manufacturing a membrane filter

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EP2126629A1 (fr) 2009-12-02
EP2126629A4 (fr) 2011-12-21

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