Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/18—Diffraction gratings
  • G02B5/1847—Manufacturing methods
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/18—Diffraction gratings
  • G02B5/1847—Manufacturing methods
  • G02B5/1857—Manufacturing methods using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams
• • 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
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/02—Pretreatment of the material to be coated
  • C23C16/0227—Pretreatment of the material to be coated by cleaning or etching
  • C23C16/0245—Pretreatment of the material to be coated by cleaning or etching by etching with a plasma
• • 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
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/04—Coating on selected surface areas, e.g. using masks
  • C23C16/045—Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• • 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
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
  • C23C16/455—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
  • C23C16/45523—Pulsed gas flow or change of composition over time
  • C23C16/45525—Atomic layer deposition [ALD]
  • C23C16/45555—Atomic layer deposition [ALD] applied in non-semiconductor technology
• • 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
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/56—After-treatment
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/18—Diffraction gratings
  • G02B5/1861—Reflection gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials
• • 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
  • G03F7/0005—Production of optical devices or components in so far as characterised by the lithographic processes or materials used therefor
  • G03F7/001—Phase modulating patterns, e.g. refractive index patterns
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
  • G03H1/04—Processes or apparatus for producing holograms
  • G03H1/18—Particular processing of hologram record carriers, e.g. for obtaining blazed holograms
  • G03H1/182—Post-exposure processing, e.g. latensification

Definitions

• This disclosure concerns diffraction gratings. In par ticular, this disclosure concerns blazed gratings.
• An ordinary surface-relief diffraction grating a so-called binary grating, comprises a plurality of ridges and grooves, wherein the tops of the ridges and the bottoms of the grooves extend parallel to each other.
• normally incident light is diffracted such that equal diffraction efficiencies are produced in both neg ative and positive diffraction orders. This effect arises from the mirror symmetry of the cross-sectional profiles of binary gratings.
• diffraction preferentially toward one or more specific diffraction orders may be desirable and diffraction into other diffraction orders may be considered optical loss.
• gratings with non-mirror symmetric cross-sectional profiles must be used.
• One example of such non-symmetric gratings is the so-called blazed grating with a triangular or saw- tooth-shaped cross-sectional profile.
• blazed gratings are manufactured using pro Devics based on grayscale lithography. Although such processes have been refined to yield gratings with ac ceptable characteristics, the features, especially, the apexes, of blazed gratings produced using grayscale li thography are generally relatively rounded due to the low contrast of typical greyscale lithography resists. Such deviation from ideal blazed profiles may reduce the diffraction efficiency of blazed gratings produced using grayscale lithography and/or increase the optical scat tering caused by such gratings.
• a method for fabricating a blazed grating comprising a ridge having a blaze facet facing a blaze facet direction and an anti-blaze facet facing an anti-blaze facet direction, the blaze facet direction and the anti-blaze facet direction extending along a grating cross-sectional plane.
• the method comprises providing a substrate and a patterned mask layer on the substrate, performing primary dry etching of the substrate such that primary ions are accelerated towards a primary etch direction to impinge on the sub strate, and performing secondary dry etching of the sub strate such that secondary ions are accelerated towards a secondary etch direction to impinge on the substrate.
• a primary projection of the primary etch direction onto the grating cross-sectional plane and a secondary pro jection of the secondary etch direction onto the grating cross-sectional plane extend perpendicular to one and the other of the blaze facet direction and the anti blaze facet direction, respectively, and ions (of the primary ions and the secondary ions) accelerated towards a direction with a projection onto the grating cross- sectional plane perpendicular to the blaze facet direc tion are collimated to form a collimated ion beam for etching the substrate.
• FIG. 1 illustrates a method for fabricating a blazed grating
• FIGs . 2A, 2B, 2C, 2D, and 2E depict a series of subsequent stages of a method for fabricating a blazed grating
• FIGs. 3A, 3B, 3C, 3D, 3E, 3F, 3G, and 3H show a series of subsequent stages of another method for fabricating a blazed grating
• FIGs. 4A, 4B, 4C, 4D, 4E, and 4F illustrate a series of subsequent stages of yet another method for fabricating a blazed grating.
• any drawing of the aforementioned drawings may be not drawn to scale such that any element in said drawing may be drawn with inaccurate proportions with respect to other elements in said drawing in order to emphasize certain structural aspects of the embodiment of said drawing.
• FIG. 1 illustrates method 100 for fabricating a blazed grating comprising a ridge having a blaze facet facing a blaze facet direction and an anti-blaze facet facing an anti-blaze facet direction, the blaze facet direction and the anti-blaze facet direction extending along a grating cross-sectional plane.
• a method for fabricating a blazed grating may be identi cal, similar, or different to the method 100 of the embodiment of FIG. 1.
• the method 100 comprises providing a substrate and a patterned mask layer 110 on the substrate, performing primary dry etching 120 of the substrate such that primary ions are accelerated towards a primary etch direction to impinge on the substrate, and performing secondary dry etching 150 of the sub strate such that secondary ions are accelerated towards a secondary etch direction to impinge on the substrate.
• dry etching may refer to removal of material by exposure to ion bombardment.
• Typical dry etching techniques include Reactive Ion Etching (RIE), Deep Reactive Ion Etching (DRIE), Induc tively Coupled Plasma Reactive Ion Etching (ICP-RIE), ion milling, Ion beam Etching (IBE), Reactive Ion Beam Etching (RIBE), and variants thereof.
• RIE Reactive Ion Etching
• DRIE Deep Reactive Ion Etching
• ICP-RIE Induc tively Coupled Plasma Reactive Ion Etching
• IBE Ion beam Etching
• RIBE Reactive Ion Beam Etching
• performing dry etching of a sub strate such that specific ions are "accelerated towards” a specific direction to impinge on the substrate may refer to the ions being provided with an average veloc ity, e.g., a drift velocity, towards the specific di rection.
• an average veloc ity e.g., a drift velocity
• such ions may be accelerated towards a specific direction by an electric field.
• a primary projection of the primary etch direction onto the grating cross-sectional plane and a secondary projection of the secondary etch direction onto the grating cross-sectional plane extend perpendicular to one and the other of the blaze facet direction and the anti-blaze facet direction, respec tively, and ions (of the primary ions and the secondary ions) accelerated towards a direction with a projection onto the grating cross-sectional plane perpendicular to the blaze facet direction are collimated to form a col limated ion beam for etching the substrate.
• such primary etch direction and secondary etch direction and utilization of a collimated ion beam for etching a substrate perpendicular to a blaze facet direction may facilitate fabricating blazed gratings with sharper or less-rounded features, e.g., apexes and/or facets.
• a "collimated ion beam” may refer to a beam of ions propagating from a collimator towards a specific etch direction, e.g., a primary etch direction or a secondary etch direction.
• a collimated ion beam may be referred to as a collimated ion beam, for example, if the ion beam has a maximum angular deviation from the primary etch direc tion of 4°, 3°, or 2°.
• a collimated ion beam is formed for etching a substrate, such maximum angular deviation may be determined at the location of the sub strate. As indicated in FIG.
• the process of performing primary dry etching 120 may optionally comprise forming a groove extending in the substrate 124 along the primary etch direction
• the method 100 may optionally comprise depositing first material into the groove 130 to form an interstitial feature
• the pro cess of performing secondary dry etching 150 may op tionally comprise utilizing the interstitial feature as an etch stop 154.
• utilization of an inter stitial feature as an etch stop while performing sec- ondary dry etching may facilitate fabrication of blazed gratings with sharper, less rounded features and/or smoother and/or more even facets.
• a method for fabricating a blazed grating may or may not comprise one or more of such features.
• a "process” may refer to a series of one or more steps, leading to an end result. As such, a process may be a single-step or a multi-step process. Additionally, a process may be divisible to a plurality of sub-processes, wherein individual sub-processes of such plurality of sub-processes may or may not share common steps.
• a “step” may refer to a measure taken in order to achieve a pre-defined result.
• an "atomic layer deposition step” may refer to a step of a process, whereby a layer is formed by atomic layer deposition.
• the method 100 may optionally comprise revealing a ridge portion 140 of the substrate prior to the process of performing secondary dry etching 150.
• re vealing a ridge portion of a substrate prior to a process of performing secondary dry etching may facilitate form ing blazed gratings without post-processing step(s), whereby portions of a substrate released during the pro cess of performing secondary dry etching are removed.
• a method for fabricating a blazed grating may or may not comprise revealing a ridge por tion of a substrate prior to a process of performing secondary dry etching.
• the process of depositing first material into the groove 130 may optionally comprise an atomic layer deposition 131 step.
• a process of depositing first material into the groove comprising an atomic layer deposition step may facilitate forming intersti tial features in narrower grooves and/or with increased uniformity.
• a process of deposit ing first material into the groove may or may not com prise an atomic layer deposition step.
• the process of providing a substrate and a patterned mask layer 110 may optionally comprise providing a plurality of elongated through-holes in a coating 111 arranged on the substrate to form the mask layer, the plurality of elongated through-holes extending perpendicular to the grating cross-sectional plane.
• a process of providing a substrate and a patterned mask layer may or may not comprise providing a plurality of elongated through-holes in a coating arranged on the substrate to form the mask layer.
• a method for fabricating a blazed grating comprises steps implementing processes corre sponding to the processes of the method 100 of the em bodiment of FIG. 1.
• a method for fabricating a blazed grating may comprise steps imple menting processes corresponding to the non-optional pro Waits of the method 100 of the embodiment of FIG. 1.
• a method for fabricating a blazed grating may comprise any number of additional processes or steps that are not disclosed herein in connection to the method 100 of the embodiment of FIG. 1.
• Steps of a method for fabricating a blazed grating im plementing processes corresponding to any of the provics of the method 100 of the embodiment of FIG. 1 need not be executed in a fixed order.
• any steps implementing a process corresponding to the pro cess of providing a substrate and a patterned mask layer 110 of the method 100 may be generally executed prior to steps implementing any process corresponding to any of the processes of performing primary dry etch ing 120 and performing secondary dry etching 150;
• any steps implementing a process corresponding to the pro cess of forming a groove extending in the substrate 124 of the method 100 may be generally executed prior to steps implementing any process corresponding to the pro cess of depositing first material into the groove 130;
• any steps implementing a process corresponding to the process of depositing first material into the groove 130 of the method 100 may be generally executed prior to steps implementing any process corresponding to the process of utilizing the interstitial feature as an etch stop 154.
• FIGs. 2A through 2E schematically depict a series of subsequent stages of a method for fabricating a blazed grating 200, which comprises a ridge 210 having a blaze facet 211 facing a blaze facet direction 212 and an anti-blaze facet 213 facing an anti-blaze facet di rection 214, the blaze facet direction 212 and the anti blaze facet 213 extending along a grating cross-sec tional plane 215, according to an embodiment.
• the grating cross-sectional plane 215 extends perpen dicular to the plane of the drawings of FIGs. 2A through 2E.
• a method for fabricating a blazed grating may comprise a series of stages similar or different to the stages of the method of the embod iment of FIG. 2.
• FIG. 2 may be in accordance with any of the embodiments disclosed with reference to and/or in conjunction with FIG. 1. Additionally or alterna tively, although not explicitly stated in the following, the embodiment of FIG. 2 may generally comprise any fea tures of any of the embodiments disclosed with reference to and/or in conjunction with FIG. 1.
• the blazed grating 200 com prises a plurality of ridges 210, each ridge of the plurality of ridges 210 having a blaze facet 211 facing the blaze facet direction 212 and an anti-blaze facet 213 facing the anti-blaze facet direction 214.
• a blazed grating may comprise at least one such ridge or a plurality of, i.e., at least two, such ridges.
• the method comprises providing a substrate 220 and a patterned mask layer 230 on the substrate 220.
• the process of providing the sub strate 220 and the patterned mask layer 230 comprises providing a coating 232 on the substrate 220 and provid ing a plurality of elongated through-holes 231 in the coating 232 to form the mask layer 230.
• the plurality of elongated through-holes 231 extends perpendicular to the grating cross-sectional plane 215.
• the substrate 220 of the embodiment of FIG. 2 may be formed of high-refractive-index polymer material(s), using any suitable application method (s), for example, spin coating, spray coating, and/or inkjet printing.
• a substrate may comprise any suitable material (s), which may be formed using any suitable pro cess (es).
• the mask layer 230 of the embodiment of FIG. 2 may be formed of aluminum oxide (AIO2) deposited by electron beam evaporation.
• a mask layer may comprise any suitable material(s), for example, inor ganic material(s), including oxide and/or nitride mate rial (s), such as aluminum oxide (A10 2 /A10 x ), titanium oxide (Ti0 2 /Ti0 2 ), silicon oxide (Si0 2 /Si0 x ) and/or sil icon nitride (Si2N3/SiN x ), which may be formed using any suitable process(es), for example, sputtering, evapora tion, Chemical Vapor Deposition (CVD), Plasma Enhanced Chemical Vapor Deposition (PECVD), Inductively Coupled Plasma Chemical Vapor Deposition (ICP-CVD), Atomic Layer Deposition (ALD), and/or variants thereof.
• CVD Chemical Vapor Deposition
• PECVD Plasma Enhanced Chemical Vap
• the method of the embodiment of FIG. 2 may constitute an example of a method for fabricating a blazed grating, whereby a blazed grating is formed onto a face of a waveguide for coupling light into the waveguide and/or out of the waveguide.
• the substrate 220 may be arranged onto a face 271 of a waveguide 270.
• a blazed grating may be formed for any suitable use(s) in any suitable application (s), for ex ample, onto a face of a waveguide for coupling light into the waveguide and/or out of the waveguide.
• the blazed grating 200 of the em bodiment of FIG. 2 is formed into an additional material layer arranged onto the waveguide 270.
• said blazed grating may or may not be arranged onto such additional material layer.
• a blazed grating may be formed directly into a waveguide.
• a "waveguide” may refer to an opti cal waveguide. Additionally or alternatively, a wave guide may refer to a two-dimensional waveguide, wherein light may be confined along a thickness direction of said waveguide.
• a "face" of a waveguide may refer to a part of a surface of said waveguide viewable from or facing a certain viewing direction. Additionally or alterna tively, faces of a waveguide may refer to surfaces suit able for or configured to confine light in said wave guide by total internal reflection.
• the method comprises per forming primary dry etching of the substrate 220 such that primary ions 121, indicated schematically by white dots, are accelerated towards a primary etch direc tion 122 to impinge on the substrate 220.
• a primary projection 123 of the primary etch direction 122 onto the grating cross-sectional plane 215 extends perpendicular to anti-blaze facet direction 214.
• a primary projection of a primary etch direction onto a grating cross-sectional plane may extend perpendicular to a blaze facet direction or an anti-blaze facet di rection.
• the process of performing primary dry etching of the embodiment of FIG. 2 comprises forming a groove 240 ex tending in the substrate 220 along the primary etch di rection 122.
• a process of per forming primary dry etching may or may not comprise forming such groove.
• an interface 222 be tween the substrate and the mask layer extends along a base plane 260, and the primary projection 123 extends perpendicular to the base plane 260.
• the base plane 260 extends perpendicular to the grating cross-sectional plane 215.
• a primary projection or a second ary projection extending perpendicular to a base plane may enable forming blazed gratings with upright anti- blaze facets, which may impart increased diffraction efficiency.
• a primary projec tion or a secondary projection may or may not extend perpendicular to a base plane.
• a "base plane” may refer to a fictitious surface along which an interface between a substrate and a mask layer extends.
• a base plane may be planar, for example, in case of a flat interface, or curved, for example, in case of a curved interface.
• the primary etch direc tion 122 may extend parallel to the grating cross-sec tional plane 215. Consequently, the primary etch direc tion 122 may extend perpendicular to the base plane 260.
• a primary etch direction or a secondary etch direction extending perpendicular to a base plane may enable utilization of a wider range of dry etching tech niques, including reactive ion etching (RIE) and ion milling.
• RIE reactive ion etching
• a primary etch direction or a secondary etch direction may or may not extend perpendicular to a base plane.
• each of a primary projection and a second ary projection may extend obliquely with respect to a base plane.
• a primary projection and a sec ondary projection extending obliquely with respect to a base plane may enable forming blazed gratings with slanted anti-blaze facets, which may, for example, fa cilitate spatially modulating diffraction efficiencies of the blazed gratings.
• the process of performing primary dry etching of the embodiment of FIG. 2 may com prise a RIE step.
• the substrate 220 may be etched, for example, using oxygen plasma.
• a process of performing primary dry etch ing may comprise any suitable step(s), for example, a RIE step and/or an ion milling step.
• the method comprises per forming secondary dry etching of the substrate 220 such that secondary ions 151, indicated schematically by black dots, are accelerated towards a secondary etch direction 152 to impinge on the substrate 220.
• a secondary projection 153 of the secondary etch direction 152 onto the grating cross-sectional plane 215 extends perpendicular to blaze facet direction 212.
• a sec ondary projection of a secondary etch direction onto a grating cross-sectional plane may extend perpendicular to a blaze facet direction or an anti-blaze facet di rection.
• the secondary ions 151 are collimated to form a collimated secondary ion beam for etching the substrate 220.
• primary ions and/or secondary ions may be collimated to form a collimated primary ion beam and/or a collimated second ary ion beam for etching a substrate.
• the process of performing secondary dry etching of the embodiment of FIG. 2 may comprise a RIBE step.
• the substrate 220 may be etched, for example, using oxygen ions.
• a pro cess of performing dry etching wherein ions are accel erated towards a direction with a projection onto a grating cross-sectional plane perpendicular to a blaze facet direction and said ions are collimated to form a collimated ion beam for etching a substrate, may com prise any suitable step(s), for example, an IBE and/or a RIBE step.
• the method further comprises a post-processing step, whereby portions of the sub strate 220 released during the process of performing secondary dry etching are removed to form the plurality of ridges 210.
• a method for fab ricating a blazed grating may or may not comprise such post-processing step.
• the post-processing step of the embodiment of FIG. 2 may be implemented as a wet cleaning step, such as, a water immersion step.
• a method for fabricating a blazed grating comprises a post-pro- cessing step, whereby portions of a substrate released during a process of performing secondary dry etching are removed to form one or more ridges
• the post-processing step may be implemented in any suitable manner, for example, as a wet cleaning step, such as, a water im mersion step.
• the primary ions 121 may exhibit a first pri mary chemical reactivity with the mask layer 230 and a second primary chemical reactivity higher than the first primary chemical reactivity with the substrate 220.
• the secondary ions 151 may exhibit a first secondary chem ical reactivity with the mask layer 230 and a second secondary chemical reactivity higher than the first sec ondary chemical reactivity with the substrate 220.
• utilization of such reactive ions for etching a substrate may increase selectivity of dry etching pro Waits, which may, in turn, facilitate fabricating blazed gratings with sharper, less rounded features.
• dry etching techniques include RIE, DRIE, ICP-RIE, RIBE and variants thereof.
• primary ions may or may not exhibit, under primary etching condi tions, a first primary chemical reactivity with a mask layer and a second primary chemical reactivity higher than the first primary chemical reactivity with a sub strate
• secondary ions may or may not exhibit, under secondary etching conditions, a first secondary chemical reactivity with the mask layer and a second secondary chemical reactivity higher than the first sec ondary chemical reactivity with the substrate.
• FIGs. 3A through 3H schematically depict a series of subsequent stages of a method for fabricating a blazed grating 200 comprising a ridge 210 having a blaze facet 211 facing a blaze facet direction 212 and an anti-blaze facet 213 facing an anti-blaze facet di rection 214, the blaze facet direction 212 and the anti blaze facet 213 extending along a grating cross-sec tional plane 215, according to an embodiment.
• the grating cross-sectional plane 215 extends perpen dicular to the plane of the drawings of FIGs. 3A through 3H.
• a method for fabricating a blazed grating may comprise a series of stages similar or different to the stages of the method of the embod iment of FIG. 3.
• FIG. 3 may be in accordance with any of the embodiments disclosed with reference to and/or in conjunction with any of FIGs. 1 and 2. Additionally or alternatively, although not explicitly stated in the following, the embodiment of FIG. 3 may generally com prise any suitable features of any of the embodiments disclosed with reference to and/or in conjunction with any of FIGs. 1 and 2.
• the method com prises providing a substrate 220 and a patterned mask layer 230 on the substrate 220, comprising providing a coating 232 on the substrate 220 and providing a plu rality of elongated through-holes 231 in the coating 232 to form the mask layer 230, as well as performing pri mary dry etching of the substrate 220 such that primary ions 121, indicated schematically by white dots, are accelerated towards a primary etch direction 122 to im pinge on the substrate 220.
• a primary projection 123 of the primary etch direction 122 onto the grating cross-sectional plane 215 extends perpendicular to anti-blaze facet direction 214.
• the pro cess of performing primary dry etching of the embodiment of FIG. 3 comprises forming a groove 240 extending in the substrate 220 along the primary etch direction 122.
• the method comprises depositing first material 250 into the groove 240 to form an interstitial feature 251 and, prior to the pro cess of depositing first material 250 into the groove 240, removing the patterned mask layer 230.
• a method for fabricating a blazed grating may or may not comprise depositing first mate rial into a groove to form an interstitial feature.
• the method may or may not comprise removing a patterned mask layer prior to a process of depositing first material into the groove.
• the first material 250 of the embodiment of FIG. 3 may be aluminum oxide (AIO2 or A10 x ) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD).
• PECVD Plasma Enhanced Chemical Vapor Deposition
• a mask layer may comprise any suitable ma terial (s), which may be formed using any suitable pro cess (es), for example, an oxide or a nitride material, such as aluminum oxide (A10 2 /A10 x ), titanium oxide (Ti0 2 /Ti0 2 ), silicon oxide (Si0 2 /Si0 x ) or silicon nitride (Si2N3/SiN x ), or a mixture thereof.
• a first material may generally be deposited using any suitable deposition method (s), for example, sputtering, evaporation, Chem ical Vapor Deposition (CVD), PECVD, Inductively Coupled Plasma Chemical Vapor Deposition (ICP-CVD), Atomic Layer Deposition (ALD), and/or variants thereof.
• s deposition method
• CVD Chem ical Vapor Deposition
• PECVD PECVD
• ICP-CVD Inductively Coupled Plasma Chemical Vapor Deposition
• ALD Atomic Layer Deposition
• the method comprises reveal ing a ridge portion 221 of the substrate 220 prior to a process of performing secondary dry etching.
• a method for fabricating a blazed grating may or may not comprise revealing a ridge portion of a substrate prior to a process of performing secondary dry etching.
• the process of revealing the ridge portion 221 of the substrate 220 may comprise an additional dry etching step.
• at least part of the first material 250 covering the ridge por tion 221 may be etched using dry etching methods.
• a method for fabricating a blazed grating comprises revealing a ridge portion of a substrate
• said process of revealing a ridge portion may be implemented in any suitable manner.
• the method comprises per forming secondary dry etching of the substrate 220 such that secondary ions 151, indicated schematically by black dots, are accelerated towards a secondary etch direction 152 to impinge on the substrate 220.
• the sec ondary ions 151 are collimated to form a collimated sec ondary ion beam for etching the substrate 220.
• the process of performing secondary dry etching comprises utilizing the interstitial feature 251 as an etch stop.
• a process of performing secondary dry etching may or may not comprise utilizing the interstitial feature as an etch stop.
• the interstitial fea ture 251 is arranged towards the anti-blaze facet di rection 214 from the ridge portion 221.
• an interstitial feature may be arranged towards a blaze facet direction or towards an anti-blaze facet direction from a ridge portion.
• an interstitial fea ture may be arranged towards the other of the blaze facet direction and the anti-blaze facet direction from a ridge portion.
• the method further comprises a post-processing step, whereby the interstitial fea ture 251 is removed.
• a post-processing step may be implemented, for example, as a wet etching step.
• a method for fabricating a blazed grating may or may not comprise such post-processing step.
• FIGs. 4A through 4F schematically depict a series of subsequent stages of a method for fabricating a blazed grating 200 comprising a ridge 210 having a blaze facet 211 facing a blaze facet direction 212 and an anti-blaze facet 213 facing an anti-blaze facet di rection 214, the blaze facet direction 212 and the anti blaze facet 213 extending along a grating cross-sec tional plane 215, according to an embodiment.
• the grating cross-sectional plane 215 extends perpen dicular to the plane of the drawings of FIGs. 4A through 4F.
• a method for fabricating a blazed grating may comprise a series of stages similar or different to the stages of the method of the embod iment of FIG. 4.
• FIG. 4 may be in accordance with any of the embodiments disclosed with reference to and/or in conjunction with any of FIGs. 1 to 3. Additionally or alternatively, although not explicitly stated in the following, the embodiment of FIG. 4 may generally com prise any features of any of the embodiments disclosed with reference to and/or in conjunction with any of FIGs. 1 to 3.
• the method comprises provid ing a substrate 220 and a patterned mask layer 230 on the substrate 220.
• the method of the embodiment of FIG. 2 may constitute an example of a method for fabri cating a blazed grating, whereby the blazed grating is formed onto a contact face of a nanoimprint stamp.
• the substrate 220 of the embodiment of FIG. 2 may be a nanoimprint stamp 280 having a contact face 281.
• the nanoimprint stamp 280 may be formed of single-crystalline silicon.
• a nanoimprint stamp may be formed of or comprise any suitable material(s).
• a nanoimprint stamp may comprise a plural ity of stacked layers formed of different materials.
• an interface 222 between the substrate 220 and the mask layer 230 extends along a base plane 260 extending perpendicular to the grating cross-sectional plane 215.
• the method performing primary dry etching of the substrate 220 such that primary ions 121, indicated schematically by white dots, are accelerated towards a primary etch direction 122 to im pinge on the substrate 220.
• the primary ions 121 are collimated to form a collimated primary ion beam for etching the substrate 220.
• primary ions may or may not be collimated to form a collimated primary ion beam for etching a substrate.
• a primary projection 123 of the primary etch direction 122 onto the grating cross-sectional plane 215 extends perpendicular to blaze facet direction 212.
• the process of performing primary dry etching of the embodiment of FIG. 4 comprises forming a groove 240 extending in the substrate 220 along the primary etch direction 122.
• the method comprises depos iting first material 250 into the groove 240 to form an interstitial feature 251.
• a method for fabricating a blazed grating may or may not comprise depositing first material into a groove to form an interstitial feature.
• the process of depositing first material 250 into the groove 240 comprises an atomic layer deposition step.
• the first material 250 of the embodiment of FIG. 3 may be aluminum oxide (AIO2 or A10 x ).
• AIO2 or A10 x aluminum oxide
• any suitable type of first material may be used.
• the method comprises re vealing a ridge portion 221 of the substrate 220 prior to a process of performing secondary dry etching.
• the process of revealing the ridge portion 221 of the substrate 220 may comprise, for ex ample, a lift-off step for removing the mask layer 230 and first material 250 covering the ridge portion 221.
• the method comprises per forming secondary dry etching of the substrate 220 such that secondary ions 151, indicated schematically by black dots, are accelerated towards a secondary etch direction 152 to impinge on the substrate 220.
• the pro cess of performing secondary dry etching comprises uti lizing the interstitial feature 251 as an etch stop.
• the interstitial feature 251 is arranged towards the blaze facet direction 212 from the ridge portion 221.
• the secondary etch direc tion 152 may extend parallel to the grating cross-sec tional plane 215. Consequently, the secondary etch di rection 152 may extend perpendicular to the base plane 260. Since the secondary etch direction 152 may extend perpendicular to the base plane 260, the process of performing primary dry etching of the embodiment of FIG. 4 may comprise a RIE step.
• the method further comprises a post-processing step, whereby the intersti tial feature 251 is removed, for example, by wet etch- m g.

Landscapes

• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Manufacturing & Machinery (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Plasma & Fusion (AREA)
• Diffracting Gratings Or Hologram Optical Elements (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=81654644

Family Applications (1)

Country Status (8)

Cited By (2)

Families Citing this family (4)

Citations (9)

Family Cites Families (98)

• 2021
  • 2021-05-17 FI FI20215575A patent/FI130664B1/fi active
• 2022
  • 2022-05-11 EP EP22723709.6A patent/EP4341730B1/en active Active
  • 2022-05-11 CN CN202280033920.6A patent/CN117413209A/zh active Pending
  • 2022-05-11 KR KR1020237041908A patent/KR20240006598A/ko active Pending
  • 2022-05-11 WO PCT/FI2022/050316 patent/WO2022243598A1/en not_active Ceased
  • 2022-05-11 US US18/560,321 patent/US12663567B2/en active Active
  • 2022-05-11 JP JP2023569921A patent/JP2024518514A/ja active Pending
  • 2022-05-16 TW TW111118262A patent/TW202303194A/zh unknown

Patent Citations (9)

Also Published As

Similar Documents

Legal Events