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WO2018148717A1 - Formation de nanomotifs en phase solution par des réseaux de stylo à faisceau - Google Patents

Formation de nanomotifs en phase solution par des réseaux de stylo à faisceau Download PDF

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Publication number
WO2018148717A1
WO2018148717A1 PCT/US2018/017968 US2018017968W WO2018148717A1 WO 2018148717 A1 WO2018148717 A1 WO 2018148717A1 US 2018017968 W US2018017968 W US 2018017968W WO 2018148717 A1 WO2018148717 A1 WO 2018148717A1
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Prior art keywords
tip
tip array
tips
μηι
array
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Inventor
Chad A. Mirkin
Zhuang XIE
Pavlo GORDIICHUK
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Northwestern University
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Northwestern University
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    • 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
    • G03F7/16—Coating processes; Apparatus therefor
    • G03F7/165—Monolayers, e.g. Langmuir-Blodgett
    • 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
    • G03F7/0002—Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
    • 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
    • G03F7/004—Photosensitive materials
    • G03F7/0047—Photosensitive materials characterised by additives for obtaining a metallic or ceramic pattern, e.g. by firing
    • 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
    • G03F7/004—Photosensitive materials
    • G03F7/038—Macromolecular compounds which are rendered insoluble or differentially wettable
    • 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
    • G03F7/2051—Exposure without an original mask, e.g. using a programmed deflection of a point source, by scanning, by drawing with a light beam, using an addressed light or corpuscular source
    • 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
    • G03F7/26—Processing photosensitive materials; Apparatus therefor

Definitions

  • Photochemical patterning has shown its ability for spatial and temporal control of the chemical composition of materials surface at the nanoscale. 1"3
  • numerous photoreactions are conducted in the solution phase, such as photo-click reactions 4"5 and photopolymerizations. 6
  • They allow the surface functionalization with diverse molecules, biomacromolecules and nanomaterials as well as the construction of complicated structures, which have found wide applications in research and
  • tip arrays comprising a plurality of tips fixed to a common substrate layer and an optional support layer, the tips formed from a high-refractive-index polymer, said high-refractive-index polymer having a refractive index of 1 .65 or greater, and each tip coated with a metal layer having a thickness of about 50 nm to about 250 nm, optionally the metal layer positioned on each tip to leave an aperture at one end of the tip.
  • the high-refractive-index polymer has a refractive index of 1 .65 to 2.
  • the high-refractive-index polymer comprises SU-8 or NOA 170.
  • the metal layer comprises gold.
  • the metal layer is arranged on each tip to leave an aperture at one end of the tip.
  • the tip array comprises a common substrate layer.
  • the common substrate comprises an elastomer, and in some cases, the common substrate comprises a mixture of
  • polydimethylsiloxane oligomers and crosslinkers e.g., Sylgard® 184.
  • Also provided herein are methods for printing a photosensitive surface comprising positioning the tip array described herein on or near the photosensitive surface, irradiating at least one tip of the tip array with a radiation source to transmit radiation through the tip to the photosensitive surface to print indicia on the photosensitive surface, and optionally moving the photosensitive surface, the tip array, or both and repeating the irradiating step.
  • the photosensitive surface comprises a self-assembled monolayer or hydrogel on a gold surface.
  • the tip array and substrate surface form a gap during the irradiating step.
  • a solvent of refractive index less than 1 .35 is present at the tip array and photosensitive surface.
  • the solvent comprises water, methanol, or acetonitrile.
  • Also provided herein are methods of making tip arrays as described herein comprising providing a mold comprising an array of recesses, optionally coating the recesses with a metal layer, applying a high-refractive-index polymer to the mold to the fill the recesses, curing the high-refractive-index polymer, casting a common substrate over the mold, optionally applying a support layer on top of the common substrate, and separating the tip array from the mold.
  • the coating of the recesses with the metal layer comprises a tilted rotational evaporation process such that the recesses are not coated with the metal layer at the tips and form the apertures.
  • the coating of the recesses with the metal layer comprises coating the metal layer over the entirety of the recesses and the metal layer at the tips of the tip array are removed to form the apertures after separating the tip array from the mold.
  • the metal layer comprises gold.
  • the curing comprises irradiation with UV light.
  • Figure 1 shows (A) a schematic of photochemical desorption of thiol self- assembled monolayers followed by Au etching.
  • PI photoinitiator
  • B finite-difference time- domain (FDTD) simulations for light propagation through a fully-metal-coated SU-8 tip (100- nm Au) and a metal-free SU-8 tip in the aqueous environment (scale bars: 500 nm); and
  • C a plot of the simulated light intensities normalized to the incident light with the propagation length through the tip apex.
  • FIG. 2 shows (A) a schematic of the fabrication process for SU-8 and NOA tip arrays: (a) spin coating of SU-8 photoresist onto a 100-nm Au-coated Si master followed by UV curing; (b) sandwiching the PDMS liquid precursor between the UV-cured SU-8 layer and a glass slide followed by PDMS curing at room temperature for 72 h; (c) peeling off the whole assembly from the Si master; (d) spin coating of PMMA layer onto the Au-coated pyramid arrays, (e) fabrication of micro-sized apertures by etching the uncovered Au on the tips; (B) a scanning electron microscopy (SEM) image of the 100-nm Au-coated SU-8 tip; (C) an SEM image of the micro-apertured SU-8 pyramid with a metal-free tip; and (D) SEM images of the SU-8 pyramid arrays with uniform micro-apertures.
  • SEM scanning electron microscopy
  • Figure 3 shows (A) a dark-field optical microscope image of typical Au patterns generated with the fully-metal-coated SU-8 tips; (B) an AFM image of sub-wavelength Au features patterned under the conditions that the tip was in contact with and lifted away from the substrate; and (C) dark-field optical microscope images of large-area nanopatterns with the tip-substrate gap less than 1 ⁇ , where from left to right the tip height was gradually decreased.
  • Figure 4 shows (A) an optical microscopy image of Au patterns written by the micro-apertured SU-8 pen array, with the size of metal-free tips in the range of 1 .5-3 ⁇ ;( ⁇ ) an atomic force microscopy (AFM) images of a typical array produced by a 1 .5- ⁇ SU-8 tip; (C) an AFM image of sub-200 nm feature produced by the metal-free tip; (D) a plot of feature area with the exposure time for metal-free tips with 1 .5- ⁇ tip size in average; (E) SEM images of Au patterns generated by metal-free tips with varied sizes; (F) a plot of the feature diameter with the exposure time for different tips; and (G) a plot of the growth rate of feature diameter with the size of metal-free tip.
  • AFM atomic force microscopy
  • Figure 5 shows (A) depicts merged optical microscope images of etched Au patterns over a 3x3 mm 2 area; (B) a schematic of the exchange of thiolated oligonucleotides followed by the DNA-directed nanoparticle assembly; (C) an optical microscopy image of the resulting Au nanoparticle patterns; (D) an SEM image of the site-selectively assembled nanoparticles with feature size ranging from -500 nm to ⁇ 2 ⁇ under varied exposure times; and (E) photopatterning of hydrogels with thiol-ene photochemistry, where the fluorescent microscope image shows the attachment of Rhodamine-labeled thiols onto the PEG hydrogel surface.
  • Figure 6 shows (A and B) simulations of light transmission through pyramidal tips in water for apertureless PDMS tips, SU-8 tips with 40-nm and 100-nm Au coating, and SU-8 tip with a 400-nm aperture; and (C) a UV-Vis transmittance spectrum of the glass substrate coated with SU-8/PDMS thin layers.
  • Figure 7 shows (A) generation of arrays of etched Au holes through the
  • Figure 8 shows (A) an optical microscope image of arrays of sub-micrometer Au features over large areas, with exposure times of 5-20 s, with the insert showing a histogram of the feature sizes at 1 5 s of exposure across a -2 x2 mm 2 patterning area; (B) an AFM image of a typical array produced by a single tip, with exposure times of 5, 1 0, 1 5 and 20 s from top to bottom; and (C) the average feature size in 5 regions over a -2x2 mm 2 patterning area.
  • beam pen lithography By combining DMD projection with scanning probe lithography, beam pen lithography (BPL) has offered a platform for photopatterning in a massively multiplexed and direct-write fashion with an inexpensive desktop instrument. 25"27 It operates millions of polymer tip arrays to direct light onto a surface through the nanoscopic apertures in each tip apex. Moreover, individual pen addressability has been realized to produce complicated patterns on the photoresists with 1 00-nm features over 1 cm 2 area. 26
  • a general materials-based approach that allows for high-speed solution-phase photochemical patterning under mild conditions while maintaining the sub-wavelength feature sizes and macroscopic patterning area.
  • the innovation is rendered by engineering the optical properties of tips made of high- refractive-index polymer material (having a refractive index of 1 .65 or greater) to realize light focusing at the tip apex in the liquid media free of the nano-apertures.
  • Massive tip arrays with different tip configurations can be fabricated, including (1 ) fully-metal-coated and (2) metal-free tips.
  • a refractive index of 1 .65 for the tip material is required for light focusing at the apex in a liquid medium with n ⁇ 1 .34, which corresponds to common solvents such as water, acetonitrile and methanol.
  • n ⁇ 1 .34 which corresponds to common solvents such as water, acetonitrile and methanol.
  • SU-8 an epoxy-based negative tone photoresist, meets the optical requirement well (n>1 .65 for ⁇ 400 nm, >50% transmittance for ⁇ >350 nm). 32 Moreover, it has been utilized as a suitable material for making plastic scanning probes with a simple molding process.
  • Contemplated polymers having refractive indices of 1 .65 and greater include SU-8 (1 .65), poly(p-phenylene ether-sulfone) (1 .6500), poly[diphenylmethane bis(4-phenyl)carbonate] (1 .6539), polyvinyl phenyl sulfide) (1 .6568), poly(styrene sulfide) (1 .6568), butylphenol formaldehyde resin (1 .6600), poly(p-xylylene) (1 .6690), poly(2-vinylnaphthalene) (1 .6818), poly(N-vinyl carbazole) (1 .6830), naphthalene- formaldehyde rubber (1 .6960), phenol-formaldehyde resin (1 .7000), poly(pentabromophenyl methacrylate) (1 .7100), NOA 170 (1 .70), and organic-inorganic composites comprising
  • a polymer with a refractive index of 1 .65 or greater can be used to prepare the tip array as disclosed herein. While SU-8 and NOA170 are specifically used in the examples and discussion herein, it is understood that other polymers having a refractive index of 1 .65 or greater can be substituted.
  • FDTD finite-difference time-domain
  • the focused light at the tip apex exhibits an intensity of >20 fold higher than the incident light, and no intensity decay was observed within the initial 0.5- ⁇ propagation. Traveling beyond 0.5 ⁇ , the light intensity starts to decrease by a factor of ⁇ 5 per 1 ⁇ .
  • the transmitted light intensity is about 30% of the incident light at the tip apex and exhibits exponential decay from the tip apex by a factor of about 10 per 1 ⁇ . But it still shows longer penetration depth with less lateral spreading in comparison with an SU-8 probe with a 400-nm aperture (Figure 6B).
  • Apertureless SU-8 tip arrays were fabricated by employing a template-stripping method ( Figure 2A, method 1 ).
  • a hydrophobic silicon mold used for making conventional polymer pen arrays (see, e.g., WO 09/132321 ) was first coated with a 100-nm- thick layer of Au by evaporation, which served as both the separation layer and the opaque coating on the final tip arrays.
  • the Au coating can be 50 nm to 250 nm, 75 nm to 150 nm, or about 100 nm.
  • Other metal coatings can be used instead of gold, such as silver, aluminum, or chromium.
  • the size of the metal-free tips that is, the edge length of the micro- apertures, can be controlled from one to tens of micrometers.
  • the light transmittance through the pen array after removing all the metal coatings was measured as about 50% at 365 nm and >80% for ⁇ >400 nm ( Figure 6C).
  • NOA 170 tip arrays can be generated using the same procedure above or a resist- free method to open micro-apertures (Figure 2A, method 2).
  • the second method comprises a tilted rotational evaporation process to produce the metal-coated silicon master with the pyramid bottom free of metal. 35
  • NOA 170 was poured onto the master, sandwiched with the glass support, and UV-cured. The addition of a soft backing elastomer is optional. Finally the whole assembly was peeled off to obtain the micro-apertured pen array.
  • the second method is not suitable for polymers with high Young's modulus (>1 GPa) such as SU-8, which will fail to be separated from the silicon master.
  • Au patterns of etched holes can be readily generated as exposed to 365 nm light for just 40 s (about 0.25 W cm “2 , about 10 J cm “2 ) or under 405 nm (about 0.15 W cm “2 ) with a dosage of about 50 J cm “2 (Figure 7A).
  • Additional X-ray photoelectron spectroscopy (XPS) characterization showed a decrease in both C1 s and S2p peaks ( Figure 7B), but no significant C-0 bonds appeared, indicating that the Au etching can be attributed to the breakage of Au-S bonds followed by the desorption of SAMs.
  • the EG 3 SAMs were employed by taking advantage of its easily wettable and bio-repelling surface.
  • the photochemical patterning performance of the fully-metal-coated pen arrays were examined with an area of about 2 x 2 mm 2 (about 400 pens). Pen arrays of different sizes are also contemplated, for example with pens (also referred to as tips) of 500 or greater, 1000 or greater, 2000 or greater, or up to 10 million.
  • the pen array was mounted onto a scanning probe system (XE-150, Park Systems) and leveled with respect to the EG 3 SAM-coated Au substrate optically.
  • the tips were then programmed to write dot arrays, in which the exposure time was set as 60 s to 180 s and the z-piezo was moved with a 0.5 ⁇ step.
  • UV light 365 nm, about 0.25 W cm "2
  • dot arrays without UV illumination were also written to determine the effect of the tip contact on the SAMs.
  • the Au substrate was rinsed and immersed in an aqueous solution containing 20 mM thiourea, 30 mM iron nitrate, 20 mM hydrochloric acid, and 2 mM octanol to etch the unprotected Au.
  • the control patterns written in dark were not seen except for some approaching dots under large applied force, indicating that the bare tip contact has negligible damage to the SAMs.
  • etched Au patterns with sub-micrometer sizes appeared until the exposure time reached 120 s and the tip was proximately close to the substrate, for instance, with a gap less than 1 ⁇ ( Figures 3A and 3C).
  • a typical array produced by the 1 .5- ⁇ metal-free tip was characterized by AFM and shown in Figure 4B.
  • the Au layer was not etched through. With increasing exposure time, the whole 50-nm-thick Au layer was etched and the feature size increased to about 1400 nm.
  • Au patterns were also produced using 405 nm light (about 0.15 W cm "2 ) with an exposure time as fast as 30 s.
  • the light intensity from the metal- free tip in the experiments was estimated to have an enhance factor of about 10 compared with the incident light. This result is in agreement with simulations that predict greater than 10-fold intensity enhancement within the 1 - ⁇ propagation length.
  • the exposure time was approximately doubled when the tip was lifted by 1 ⁇ , in accordance with the light intensity at the 1 - ⁇ propagation length being reduced to half of that at the tip apex in the simulation as well.
  • the area of each feature was then plotted with the exposure time (Figure 4D). It was shown that by lifting the tip to vary the light intensity, the growth of the feature area exhibited distinct behaviors.
  • the SAMs are not completely damaged by the photoinitiators, leading to partial etching of the Au and slow increase of the feature size. After a certain time, a large portion of SAMs can be removed to allow the full etching of Au.
  • the feature growth rate herein can be determined by the spatial distribution of the light beam as well as the equilibrium between the photodecomposition and the diffusion of photointiators. Finally, at a longer reaction period, the growth rate could drop down and form the curve with the plateau due to the photoinitiator consumption at the local illuminated areas.
  • the feature diameter exhibited first-order function with the exposure time for all the tips.
  • the growth rates in these linear ranges were found to increase dramatically when the tip size is larger than 3.5 ⁇ ( Figure 4G). Without being bound by theory, it is hypothesized that this could result from the nonlinear increase of the radical generation rate with varied light intensities.
  • each feature can be patterned as fast as 2 s using 365 nm light (about 0.25 W cm "2 , 34 mM LAP) and the patterning process can be finished within 15 min.
  • sub- wavelength patterning can be also performed with photoinitiators dissolved in methanol, such as bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide (Ciba ® IRGACURE ® 819).
  • the patterning speed can be further increased, especially under light with ⁇ >400 nm, due to the higher absorption efficiency of the photoinitiators.
  • the substrate upon site-selective illumination was immersed in the solution containing thiolated
  • the tip arrays were exploited to pattern the surface of hydrogels by thiol-ene click reactions.
  • Photocrosslinked hydrogels made from poly(ethylene glycol) diacrylate (PEGDA, average Mn 700) were immersed in an aqueous solution added with Rhodamine-labeled thiol molecules and LAP photoinitiators.
  • PEGDA poly(ethylene glycol) diacrylate
  • Rhodamine-labeled thiol molecules and LAP photoinitiators Upon exposure to 365 nm light (-10 mW cm "2 ) through the SU-8 tip array, fluorescent patterns were obtained with irradiation for 1 min ( Figure 5E).
  • tip arrays including a plurality of tips fixed to a common substrate layer and an optional support layer, wherein the tips are formed from a high- refractive-index polymer having a refractive index of 1 .65 or greater.
  • the high refractive index polymers contemplated can include moldable polymers with a refractive index of greater than 1 .65, greater than 1 .7, greater than 1 .75, greater than 1 .8, greater than 1 .85, greater than 1 .9, greater than 1 .95, greater than 2, or greater than 2.1 .
  • the polymer can have a refractive index of 1 .65 to 1 .75, 1 .75 to 2, 1 .6 to 1 .7, 1 .7 to 1 .8, 1 .8 to 1 .9, or 1 .9 to 2.
  • the polymer can have a refractive index of 1 .65 to 1 .7, 1 .7 to 1 .75, 1 .75 to 1 .8, 1 .8 to 1 .85, 1 .85 to 1 .9, 1 .9 to 1 .95, or 1 .95 to 2.
  • Contemplated high refractive index polymers include organic polymers or organic- inorganic composite materials comprising an organic polymer matrix and inorganic nanoparticles.
  • the inorganic nanoparticles can comprise metal oxide nanoparticles.
  • the high refractive index polymer comprises SU-8, poly(p-phenylene ether-sulfone), poly[diphenylmethane bis(4-phenyl)carbonate], polyvinyl phenyl sulfide), poly(styrene sulfide), butylphenol formaldehyde resin, poly(p-xylylene), poly(2-vinylnaphthalene), poly(N- vinyl carbazole), naphthalene-formaldehyde rubber, phenol-formaldehyde resin,
  • the high refractive index polymer comprises SU-8 or NOA 170.
  • the high refractive index polymer comprises an organic-inorganic composite comprising a polymer matrix and a metal oxide nanoparticle.
  • the metal oxide nanoparticle comprises Ti0 2 , ZnO, Zr0 2 , or Ce0 2 .
  • Each tip is coated with a metal layer.
  • the metal layer is positioned on each tip to leave an aperture at one end of the tip. In other cases, the metal layer completely coats the tip such that there is no aperture.
  • the tips are coated with a metal where the metal comprises gold, silver, aluminum, titanium, or chromium. In some cases, the metal comprises gold.
  • the metal layer can have a thickness of 50 nm to 250 nm, 75 nm to 150 nm, or 100 nm.
  • the aperture in the tip can be formed by any suitable method, including, for example, focused ion beam (FIB) methods or using a lift-off method.
  • the tips can be immersed in an etching solution to remove a portion of the metal layer and form the aperture by exposing the material of the tip.
  • the size of the aperture can be controlled during fabrication by appropriate methods known to those skilled in the art.
  • the aperture can have a diameter of 1 ⁇ to 10 ⁇ , 3 ⁇ to 10 ⁇ , 1 ⁇ to 3 ⁇ , or 5 ⁇ to 10 ⁇ .
  • the minimum aperture diameter can be 1 , 1 .5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or 10 ⁇ .
  • the maximum aperture diameter can be 1 , 1 .5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or 10 ⁇ .
  • the tip arrays comprise tips which can be designed to have any shape or spacing (pitch) between them, as needed.
  • the shape of each tip can be the same or different from other tips of the array, and preferably the tips have a common shape.
  • Contemplated tip shapes include spheroid, hemispheroid, toroid, polyhedron, cone, cylinder, and pyramid (trigonal or square).
  • the tips have a base portion fixed to the tip substrate layer.
  • the base portion preferably is larger than the tip end portion.
  • the base portion can have an edge length of 1 ⁇ to 40 ⁇ , 1 ⁇ to 20 ⁇ , 1 ⁇ to 10 ⁇ , or 1 .5 ⁇ to 3 ⁇ .
  • the minimum edge length can be 1 , 1 .5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18, 19, 20 22, 24, 26, 28, 30, 32, 34, 36, 38, or 40 ⁇ .
  • the maximum edge length can be 1 , 1 .5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, or 40 ⁇ .
  • a tip array can contain 500 or more tips, 1000 or more tips, 2000 or more tips, or up to 10 million tips.
  • the tips are arranged in a regular periodic pattern.
  • the tips are identically-shaped.
  • the tips have a pyramidal shape.
  • the tip array can optionally be attached to a support layer, for example, a support layer formed from glass, silicon, quartz, ceramic, polymer, or any combination thereof.
  • the support layer is preferably rigid and has a planar surface upon which to mount the tip array and can act as a rigid support.
  • the support layer comprises a glass slide.
  • the tip array further comprises a common substrate.
  • the common substrate when present, can comprise any polymer compatible with the high refractive index polymer of the tips. "Compatible with” indicates that neither the polymer of the common substrate nor the high refractive index polymer become unstable or degrade upon contact with each other.
  • the common substrate comprises an elastomer.
  • the common substrate can comprise a polymer having linear or branched backbones, and can be crosslinked or non-crosslinked. Cross-linkers refer to multifunctional monomers capable of forming two or more covalent bonds between polymer molecules.
  • Non-limiting examples of cross-linkers include such as trimethylolpropane trimethacrylate (TMPTMA), divinylbenzene, di-epoxies, tri-epoxies, tetra-epoxies, di-vinyl ethers, tri-vinyl ethers, tetra-vinyl ethers, siloxanes ⁇ e.g., polydimethylsiloxane or Sylgard® 184), and combinations thereof.
  • the common substrate comprises a mixture of polydimethylsiloxane oligomers and crosslinkers ⁇ e.g., Sylgard® 184).
  • the high refractive-index polymer, common substrate layer, and support layer when present are at least translucent. In various cases, the high refractive-index polymer, common substrate layer, and support layer, when present are transparent.
  • the tip portion of the tip arrays can be made with a master mold prepared by techniques known in the art ⁇ e.g., conventional photolithography and subsequent wet chemical etching), to comprise an array of recesses.
  • the mold can be engineered to contain sufficient recesses to provide as many tips arrayed in any fashion desired.
  • the tips of the tip array can be any number desired, and contemplated numbers of tips include 500 tips to 10 million tips.
  • the number of tips of the tip array can be greater than 500, greater than 1000, greater than 2000, greater than 5000, greater than 10000, greater than 50000, greater than 100000, greater than 500000, greater than 1 million, greater than 2 million, greater than 5 million, or up to 10 million tips.
  • the mold recesses can be coated with a metal to form a metal layer.
  • the metal layer can be disposed on the tips by any suitable process, including for example, via an evaporation process to deposit the metal layer.
  • the metal layer can comprise any metal desired, including e.g., gold, silver, aluminum, titanium, or chromium. In various cases, the metal layer comprises gold.
  • Depositing the metal layer can comprise sequential deposition of more than one metal, e.g., deposition of Ti followed by deposition of Au.
  • the metal layer can have any thickness desired. In some cases, the metal layer has a thickness of 50 nm to 250 nm, 75 nm to 150 nm, 90 nm to 1 10 nm, or 100 nm.
  • the tip array can be formed by any suitable process via applying a high refractive- index polymer to the mold to fill the recesses.
  • applying the polymer comprises coating, e.g., spin-coating, the mold with a high refractive-index polymer.
  • the polymer is cured after application to the mold by a suitable method.
  • the curing comprises irradiation with UV light.
  • a common substrate layer is applied over the mold following curing of the tips.
  • applying the common substrate layer comprises coating e.g., spin-coating.
  • the common substrate layer comprises polydimethylsiloxane (PDMS).
  • a support layer can be applied on top of the common substrate.
  • the support layer comprises glass, silicon, quartz, ceramic, polymer, or any combination thereof.
  • the support layer comprises glass ⁇ e.g., a glass slide).
  • the tip array is separated from the mold after application of the support layer.
  • An aperture in the metal layer can be formed by any suitable method, before or after application of the high refractive-index polymer.
  • an aperture is formed by applying the metal layer to the mold via a tilted rotational evaporation process such that the mold recesses are not coated with the metal layer at the tips and form the apertures when the high refractive-index polymer is subsequently applied.
  • an aperture is formed by coating the metal layer over the entirety of the recesses and removing the metal layer from the tips of the tip array to form the apertures after separating the tip array from the mold.
  • removing the metal layer from the tips of the tip array comprises applying a protective layer to the tip array such that a portion of the tips of are exposed and removing the metal layer at the exposed tips by etching.
  • Beam pen lithography can be performed using any suitable platform, for example, a Park AFM platform (XEP, Park Systems Co., Suwon, Korea) equipped with a halogen light source.
  • a Zeiss microscope can be used with a light source having a wavelength in a range of about 360 nm to about 450 nm. Movement of the tip array when using the Zeiss microscope can be controlled, for example, by the microscope stage.
  • a high refractive-index polymer tip array as described herein is positioned on or near a photosensitive layer of a surface to be printed, for example, a self- assembled monolayer (SAM) or hydrogel on an Au substrate, followed by exposure ⁇ e.g. illumination) of the top surface (e.g., the support layer) of at least one tip, or preferably the tip array, with a radiation source, optionally through a photomask.
  • SAM self- assembled monolayer
  • the radiation is transmitted through the high refractive index polymer tip ⁇ i.e., the tip end), thereby printing indicia on the surface.
  • the tip array and/or the surface can be moved during patterning to form the desired indicia. For example, in some cases, the tip array is moved while the surface is held stationary. In other cases, the tip array is held stationary while the surface is moved. In still other cases, both the tip array and the substrate are moved.
  • the tip array and surface can be leveled with respect to one another .
  • the leveling can be assisted by the transparent, or at least translucent nature of the tip array and tip substrate layer, which allow for detection of a change in reflection of light that is directed from the top of the tip array ⁇ i.e., behind the base of the tips and common substrate) through to the surface.
  • the intensity of light reflected from the tips of the tip array increases upon contact with the surface ⁇ e.g., the internal surfaces of the tip array reflect light differently upon contact).
  • the tip array and/or the surface can be adjusted to effect contact of substantially all or all of the tips of the tip array to the substrate surface.
  • the tip array and common substrate preferably are translucent or transparent to allow for observing the change in light reflection of the tips upon contact with the substrate surface.
  • any support layer to which the tip array is mounted is also preferably at least transparent or translucent.
  • Radiation can have a wavelength of 200 nm to 800 nm, e.g., 380 nm to 420 nm, for example 365 nm, 400 nm, or 436 nm.
  • the radiation comprises UV light e.g. light having a wavelength of 200 to 400 nm.
  • the radiation can have a minimum wavelength of 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, or 800 nm.
  • the radiation can have a maximum wavelength of 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, or 800 nm.
  • the photosensitive layer of the surface to be printed can be exposed by the radiation transmitted through the polymer tip for any suitable time, for example from 1 second to 5 minutes, or 20 seconds to 120 seconds.
  • the minimum exposure time can be 1 , 2, 3, 4, 5 ,6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 1 10, or 120 seconds.
  • the maximum exposure time can be 1 , 2, 3, 4, 5 ,6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 1 10, or 120 seconds.
  • the distance between tip array and the surface can form a gap during the irradiating step.
  • the gap is 0.5 to 1 .5 ⁇ , e.g., 0.5, 0.6, 0.7, 0.8, 0.9, 1 .0, 1 .1 , 1 .2, 1 .3, 1 .4, or 1 .5 ⁇ .
  • tip array and the surface do not form a gap ⁇ e.g., 0 ⁇ ) during the irradiating step such that the tip array and surface are in contact with each other.
  • the surface can be printed using the tip array disclosed herein a plurality of times, wherein the tip array, the surface or both move to allow for different portions of the surface to be irradiated for printing.
  • the time of each contacting step can be the same or different, depending upon the desired pattern.
  • the shape of the indicia or patterns has no practical limitation, and can include dots, lines (e.g., straight or curved, formed from individual dots or continuously), a preselected pattern, or any combination thereof.
  • the indicia resulting from the disclosed methods can have a high degree of sameness, and thus can be uniform or substantially uniform in size, and preferably also in shape.
  • the individual indicia feature size (e.g., a dot or line width) is highly uniform, for example within a tolerance of 5%, or 1 %, or 0.5%.
  • the tolerance can be 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, or 0.1 %.
  • Non-uniformity of feature size and/or shape can lead to roughness of indicia that can be undesirable for sub-micron type patterning.
  • the feature size can be 10 nm to 1 mm, 10 nm to 500 ⁇ , 10 nm to 100 ⁇ , 200 nm to 100 ⁇ , 200 nm to 50 ⁇ , 200 nm to 10 ⁇ , 200 nm to 5 ⁇ , or 200 nm to 1 ⁇ .
  • Feature sizes can be less than 5 ⁇ , less than 4 ⁇ , less than 3 ⁇ , less than 2 ⁇ , less than 1 ⁇ , less than 900 nm, less than 800 nm, less than 700 nm, less than 600 nm, less than 500 nm, less than 400 nm, less than 300 nm, less than 200 nm, less than 100 nm, or less than 90 nm.
  • the feature size is 200 nm to 5 ⁇ .
  • a solvent of refractive index less than 1 .35 can be present at (or between) the tip array and photosensitive surface.
  • the solvent comprises water, methanol, acetonitrile, or combinations thereof.
  • the solvent further comprises a photoinitiator. In some cases, the
  • photosensitive substrate comprises e.g. an Au surface modified with 1 -dodecanethiol or (1 1 - mercaptoundecyl) tri(ethylene glycol) (EG 3 ) and present is an aqueous solution containing 1 % (w/v, 34 mM) photoinitiator lithium phenyl(2,4,6-trimethylbenzoyl)phosphinate (LAP)).
  • the method can further include developing the photosensitive layer, for example by any suitable process known in the art.
  • a printed surface can be contacted with a species, e.g., thiolated oligonucleotides, for further derivatization.
  • a template-stripping method was employed to fabricate the SU-8 beam pen arrays.
  • Silicon masters with recessed pyramidal microwells (40 ⁇ edge length, 100 ⁇ pitch) were prepared according to previous published protocols.
  • a layer of 100 nm Au and a 5-nm Ti layer were sequentially evaporated onto the silicon masters using an electron-beam evaporation system (Kurt J. Lesker Co., USA).
  • SU-8 negative tone photoresist (SU-8 5, MicroChem Inc., USA) was spin-coated onto the metal-coated masters (1000 rpm, 60 s) and soft-baked at 65°C for 2 min and 95°C for 5 min.
  • PMMA950 A1 1 poly(methyl methacrylate)
  • MicroChem Inc., USA poly(methyl methacrylate)
  • PMMA950 A1 1 poly(methyl methacrylate)
  • the PMMA coating was repeated for one more time to ensure complete coverage.
  • the pen array was immersed in an etching solution (Gold Etchant TFA, Transense Company Inc., USA) for 40 s to remove the metal coating on the top parts of pyramids.
  • the spin speed was adjusted to tune the etched portions on the pyramids.
  • an n-type ⁇ 100> silicon wafer with 500-nm thermally grown Si02 was evaporated with a layer of 2 nm Ti and 50 nm Au.
  • the Au-coated substrate was immersed in a 1 mM ethanolic solution of 1 1 -mercaptoundecyl tri(ethylene glycol) (EG 3 , Sigma-Aldrich) at 4°C for at least 24 hrs.
  • EG 3 1 1 -mercaptoundecyl tri(ethylene glycol)
  • Apertureless SU-8 tip arrays were mounted onto a scanning probe platform (XE150, Park Systems) and leveled to the SAM-modified Au substrate optically.
  • a droplet of an aqueous solution of photoinitiator lithium phenyl(2,4,6- trimethylbenzoyl)phosphinate (LAP, Tokyo Chemical Industry Co., Ltd.) was injected into the area between the tip arrays and the substrate.
  • Hydrogels was made by photopolymerization of poly(ethylene glycol) diacrylate (PEGDA, average Mn 700, Sigma-Aldrich) with 2,2- dimethoxy-2-phenylacetophenone (DMPA, 1 wt%) as the photoinitiator.
  • PEGDA poly(ethylene glycol) diacrylate
  • DMPA 2,2- dimethoxy-2-phenylacetophenone
  • Rhodamine-labeled PEG thiol Mn 5000, Nanocs Inc.
  • 34 mM LAP 34 mM LAP. Then patterning with SU-8 tip array on the hydrogel surface was conducted through 365 nm UV illumination ( ⁇ 10 mW cm-2, 1 min). The patterned hydrogel was thoroughly rinsed with Dl water and characterized with fluorescence microscopy.
  • the Au substrate was placed in an etching solution consisting of 20 mM thiourea, 30 mM iron nitrate, 20 mM hydrochloric acid, and 2 mM octanol in water for 3 min to yield hole features of Au.
  • the Au substrate was immersed in a single-strand DNA solution (1 ⁇ , 1 M NaCI) for 1 h, followed by the hybridization with the complementary linkers and the attachment of oligonucleotide-modified gold nanoparticles. Patterns were characterized using optical microscopy (Axiovert-Zeiss), atomic force microscopy (Dimension Icon, Bruker), and scanning electron microscopy (SU8030, Hitachi).
  • FDTD simulations were performed using a commercial package (Lumerical FDTD solutions v.8.1 1 .337).
  • the refractive indices of environment and SU-8 pyramid were assumed to be 1 .34 and 1 .65, respectively, around the wavelength of the light source.
  • the pyramid height to base edge ratio was 0.707 and the pyramid base edge size in the simulation was reduced to 3 ⁇ due to computational limitation.
  • the total field scattered field (TFSF) plane wave source was used to avoid the light interaction with the simulation boundary.
  • the light polarization was parallel to the base edge direction of the pyramid.
  • the wavelength of the injected light was 350-450 nm (a pulse in the time domain).
  • the Perfectly Matched Layers (PML) boundary condition was used to absorb the electromagnetic fields at the simulation boundary.
  • Electric fields were recorded in five different 2D monitors in the time domain following the light pulse injection, and they were Fourier-transformed into the frequency domain to generate the local intensity profile.
  • Three horizontal 2D monitors were located at the top, middle and bottom planes of the photoresist, and two vertical monitors were parallel to the pyramid base edges.
  • the spectral profile of the light source (LED) was addressed by averaging the intensity.
  • the broadband results are convoluted with a narrow weighting function (Amax ⁇ 400nm) to analyze the response around wavelength of 400 nm. All the simulation images are obtained at 400 nm.

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Abstract

La présente invention concerne des réseaux de pointes et des procédés qui permettent une formation de motifs photochimiques à haut rendement, à haute résolution et en phase solution à l'aide d'une lithographie par stylo à faisceau. Par l'exploration de matériaux polymères à indice de réfraction élevé pour fabriquer des pointes pyramidales entièrement revêtues de métal ou dépourvues de métal, la lumière traversant ces pointes dans la phase liquide peut être focalisée sur des régions de sous-longueur d'onde sans avoir besoin d'ouvertures nanoscopiques. Par conséquent, des réseaux massifs de telles sondes pyramidales ont été mis en évidence pour déclencher des photoréactions radicalaires de surface simultanément dans une solution aqueuse pour former des monocouches auto-assemblées (SAM), la plus petite taille de caractéristique étant inférieure à 200 nm. En outre, l'approche photochimique permet la génération rapide de caractéristiques uniformes sur de grandes surfaces. Cet outil simple et sans masque peut être utilisé pour effectuer diverses réactions photochimiques pertinentes pour les domaines de la chimie, de la biologie et de la science des matériaux à des échelles multiples pour une fonctionnalisation de surface et un criblage combinatoire à haut rendement.
PCT/US2018/017968 2017-02-13 2018-02-13 Formation de nanomotifs en phase solution par des réseaux de stylo à faisceau Ceased WO2018148717A1 (fr)

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CN115171093A (zh) * 2022-06-20 2022-10-11 中国人民解放军96963部队 机械结合面参数计算方法及装置

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