Lithography mask methods and composition

Abstract

The disclosure relates to photolithography systems, methods and masks for semiconductor fabrication, focusing on overcoming diffraction-limited critical dimensions in optical lithography. Current extreme ultraviolet (EUV) systems typically achieve critical dimensions of -12-20 nm. However, finer critical dimension yields are constrained by stochastic effects including photon shot noise, unacceptable line-edge roughness, and unacceptable random bridging or break defects. These random failures, rather than systematic aberrations, dominate yield loss for the 12-20 nm features' technologies. Attempts to reduce defects by increasing source power or resist sensitivity worsen the resolution / roughness / sensitivity trade-off, further narrowing the process window. Therefore, new lithographic methods are provided, producing sub- 10 nm features with high fidelity, low probability of stochastic defectivity, and compatibility with both 300 mm and the underserved 200 mm fabrication infrastructures.

Description

LITHOGRAPHY MASK METHODS AND COMPOSITIONBACKGROUND

[0001] The disclosure is directed to mask compositions for photolithography and their method of use in semiconductor manufacturing processes. Specifically, the disclosure is directed to a novel photolithography mask comprising nanoscale patterns, operable to absorb electromagnetic radiation and consequently generate a chemical reaction in a resist substrate.

[0002] Photolithography remains the dominant technique for creating small features in semiconductor manufacturing. The current state-of-the-art typically employs extreme ultraviolet (EUV) lithography, using 13.5 nm wavelength light to produce small features in high-volume manufacturing. The technology is essential for producing integrated circuits (ICs) with ever-smaller transistors, powerful and energy-efficient processors, memory devices, photonic crystals and other nanostructures and metastructures that manipulate light at the nanoscale for applications in optics and telecommunications, Micro-electromechanical systems (MEMS) and nano-electromechanical systems (NEMS), advanced biomedical devices, including drug delivery systems, biosensors, and lab- on-a-chip technologies.

[0003] The photolithography process, typically involves coating a silicon wafer with resist, exposing it to light through a patterned mask, and then developing and etching or depositing the pattern onto the wafer. For complex integrated circuits, this cycle may be repeated. Currently, the minimum feature size achievable is limited mainly by the wavelength of light used, and the numerical aperture of the lens system, as described by the equation:CD = ki * ( / NA) (EQU. 1) where: - CD is the critical dimension,- X is the wavelength,- NA is the numerical aperture, and- ' k i is a process-dependent factor.

[0004] Regardless of its capabilities, current photolithography methods face several challenges rooted in fundamental physics and materials science. The primary limitation is the diffraction limit, which constrains the minimum feature size, or critical dimension (CD), that can be achieved using optical methods. As feature sizes approach the sub- 10 nm regime, far below thewavelength of light used even in Extreme Ultraviolet (EUV) systems, diffraction effects become profoundly pronounced, leading to severely reduced pattern fidelity, increased line edge roughness (LER), and a catastrophic loss of process window. While increasing the numerical aperture (NA) of the projection optics can theoretically improve resolution, the depth of focus decreases quadratically, making it exceptionally challenging to maintain focus across the entire wafer surface, especially for the non-planar topographies inherent in advanced device architectures. Furthermore, the transition to EUV necessitates a complete paradigm shift from refractive to reflective optics, employing complex multilayer Bragg reflector mirrors and operating within high-vacuum systems to prevent absorption of the 13.5 nm radiation. The high cost of EUV light sources, their operational maintenance, and the formidable difficulty in developing photoresist materials that simultaneously satisfy the competing demands of high resolution, low LER, and high sensitivity — the so-called RLS trade-off — severely limits widespread adoption and presents an ongoing barrier to cost-effective scaling.

[0005] To circumvent the diffraction limit of photon-based systems, alternative lithographic techniques have been developed, presenting their own distinct sets of drawbacks. X-ray lithography, for example, can theoretically reduce the limit of diffraction to approximately 1 nm and has been used to produce features as small as 20 nm. However, the requirement of X-ray source, such as a synchrotron, makes it impractical for high-volume manufacturing. The fabrication of transmissive masks for X-ray systems is also exceptionally challenging. For mask production itself, particularly for the complex photomasks used in systems such as deep UV (DUV) and extreme UV (EUV), direct- write technologies are indispensable. Electron beam lithography (EBL), which patterns a surface by modulating a resist material with a focused particle beam of impinging electrons, and ion beam lithography (IBL), which employs a similar principle with ions, are the main methods for mask writing. However, both methods are inherently serial processes, where each wafer or mask pattern is written pixel by pixel, making them orders of magnitude too slow for direct wafer fabrication in an industrial setting. In addition, the pattern area is typically limited, and these particle-based lithography technologies are known to create substrate damage and other process-induced defects that can be detrimental to device performance. The cost and time required for fabricating a single advanced mask set remain exorbitant, often taking between one and two months.

[0006] Beyond deterministic optical effects, the most salient barrier to extending EUV lithography is the rise of stochastic phenomena. At the photon and molecular scales relevant to printing ~36 nm pitch contact holes and 32 nm pitch line / space patterns (and even more so at tighterpitches), the inherent randomness of photon arrival (e.g., photon shot noise) and discrete chemical events within the resist (e.g., acid generation, diffusion, and quenching), leads to stochastic printing failures. These are not systematic errors that can be corrected with techniques like optical proximity correction (OPC) but rather, are random, non-repeating defects such as micro-bridges (or shorts) between lines or breaks in a line. The probability of these stochastic defects increases exponentially as feature sizes shrink, representing the primary limiter of yield for logic devices at the 5 nm node and beyond. It is noted, that a process ‘node’ designation does not map to a single physical dimension; for example, in the most advanced commercially available so-called ‘3 nm node,’ the critical half-pitches are -12-16 nm. Mitigating these effects requires a holistic co-optimization of the light source, mask composition, resist chemistry, and etching processes.

[0007] Furthermore, the path to today's scaled nodes was paved by the intensive use of multipatterning techniques, which remain critical for layers where EUV is not yet cost-effective or feasible. Processes like Self-Aligned Double Patterning (SADP) and Self-Aligned Quadruple Patterning (SAQP) use a combination of lithography, thin-film deposition, and anisotropic etching to multiply the feature density defined by an initial lithographic step. While effective, these techniques introduce immense process complexity, significantly increase cycle time, and place extreme demands on overlay control between successive layers. Compounding these technical hurdles is an industry concentration where the development of state-of-the-art tooling is exclusively focused on 300mm silicon wafer platforms. This economic reality creates circumstances where advanced lithography support for emerging compound semiconductor platforms like Gallium Nitride (GaN) or Silicon Carbide (SiC), often processed on 200mm wafers or smaller, is effectively unavailable, further constraining innovation in those fields.

[0008] It would therefore be beneficial to develop new nano-scale lithography techniques that would address the current shortcomings.SUMMARY

[0009] Disclosed, in various exemplary implementations, are novel photolithography masks comprising nanoscale patterns, the patterns being operable to absorb electromagnetic radiation and consequently generate a chemical reaction in a resist substrate.

[0010] In an exemplary implementation, provided herein is a photolithography method, comprising: contacting a resist substrate with a lithography photomask comprising a nanoscale pattern;exposing the lithography photomask to a source of electromagnetic radiation (EMR) at a first wavelength for a predetermined time, wherein the mask is operable to absorb the EMR and induces a reaction in the resist substrate; removing the lithography photomask; and developing the resist substrate.

[0011] In another exemplary implementation, provided herein is a lithography photomask comprising nanoscale pattern, or voids defined by the nanoscale pattern, adapted sized and configured to absorb electromagnetic radiation (EMR) and consequently generate a reaction in a resist substrate abutting the lithography photomask upon exposure to the EMR

[0012] These and other features of the lithography photomask comprising a nanoscale patterns, operable to absorb electromagnetic radiation and consequently generate a reaction in a resist substrate, will become apparent from the following detailed description when read in conjunction with the figures and examples, which are exemplary, not limiting.BRIEF DESCRIPTION OF THE FIGURES

[0013] For a better understanding of the lithography photomask comprising a nanoscale patterns, operable to absorb electromagnetic radiation and consequently generate a reaction in a resist substrate, with regard to the exemplary implementations thereof, reference is made to the accompanying examples and figures, in which:

[0014] FIG. 1A, is a schematic showing an exemplary implementation of the lithography method, with FIG. IB, illustrating the method using spacers;

[0015] FIG. 2A shows the mask pattern; FIG. 2B an enlarged view with resist coverage highlighting reacted areas (one circled); FIG. 2C the simulated plasmonic response; FIG. 2D an SEM image of the enlarged, non-optimized pattern formed on silicon substrate; FIG. 2E an SEM image of 4 nm resist dots forming a pattern.

[0016] FIG. 3, an SEM image of a mask composed of Au triangles fabricated by EBL (left), with an enlarged section depicted on the right;

[0017] FIG. 4A, and 4B, depict SEM images of the transferred pattern at two exposure periods, with FIG.s 4C illustrating size confirmation of 4B using AFM;

[0018] FIG.s 5A-5D show the effect of the distance between the mask and the resist surface on the size of the features transferred, showed schematically (top), SEM image (middle) and AFM confirmation (bottom); d is the dot diameter and h refers to height.

[0019] FIG. 6 depicts the expected effect of the mask feature size (square patterns) on the transferred feature, where SEM images of 20 nm-thick Au square with sides of 20, 30, 40, and 50 nm are shown at the bottom, with the corresponding simulated plasmonic response (top image), at the indicated wavelength;

[0020] FIG. 7A, is a perspective view schematic showing a mask with trench features fabricated using the methods disclosed, with FIG. 7B illustrating a trench’s cross section and simulated plasmonic response, while FIG 7C presents simulated response from top view, and FIG. 7D, SEM image depicting the formed trenches on the substrate;

[0021] FIG. 8A, is a perspective view schematic showing a mask with line features, fabricated using the methods disclosed, with FIG. 8B illustrating the cross section of a single line, and simulated response, FIG 8C simulates the expected response from top view, while FIG. 8D depicting SEM image of a mask containing lines, and another section of the mask showing lines with various dimensions and pitches is depicted in FIG. 8E;

[0022] FIG. 9A, is a schematic showing a wedge formed using the methods disclosed, with FIG. 9B depicting the simulated response upon absorption of EMR, FIG. 9C showing an AFM of a mask comprising of wedges, FIG. 9D an enlarged section of the inset in FIG. 9C, and FIG. 9E the AFM line profile analysis;

[0023] FIG. 10 illustrates the simulated effect of exposure of various materials to specific EMR wavelength and the resulting response; and

[0024] FIG. 11 depicts SEM image of resist lines formed (left), with an and AFM confirmation (right).DETAILED DESCRIPTION

[0025] Provided herein are exemplary implementations of mask compositions for photolithography and their method of use in semiconductor manufacturing processes. Specifically, provided herein are systems and methods for forming photolithography mask comprising nanoscale patterns, operable to absorb electromagnetic radiation and consequently generate a chemical reaction in a resist substrate.

[0026] Optical lithography, the primary method for high-volume Complementary MetaL Oxide-Semiconductor (CMOS) fabrication, using a wavelength of 192 nanometers (nm), has reached its physical limitations in terms of the smallest achievable pitch in a single patterning process, whichis approximately 80 nm. Pitch refers to the distance between repeating features in a pattern, such as the center-to-center distance between adjacent lines.

[0027] To create more densely packed integrated circuits and maintain the trajectory predicted by Moore's Law for feature sizes approaching single-digit nanometers, the semiconductor industry has introduced multi -patterning techniques. For example, double patterning involves splitting a complex pattern into two complementary patterns that are exposed separately and then combined. This allows for the creation of dense and complex arrays, such as a 40 nm line pattern, by patterning alternating lines in two separate steps. Similarly, triple patterning extends this concept by dividing the pattern into three separate exposures, enabling the production of even smaller features, such as a 27 nm line pattern, by exposing every third line in each of the three patterning steps. These multipatterning extensions have been adopted despite the inherently higher manufacturing costs associated with multiple exposure and etching steps. For example, double patterning essentially doubles the number of lithography and etching steps, increasing production time and material costs, as well as the risks for malfunctions.

[0028] Consequently, and in an exemplary implementation, provided herein is a novel method for nanoscale lithography, achieving true single nanometer features of about 1 nm and about 4 nm in diameter. In certain exemplary implementations, the methodology uses plasmon-enhanced phenomena for promoting a specific set of reactions in a controlled and highly localized manner, with focus on the polymerization / degradation of a (photo) resist substrate. The mask is based on, for example plasmonic nano antennae. Illumination with actinic radiation near or at the plasmonic peak promotes a reaction in the vicinity of the antennae hot spots, inducing changes in the abutting resist substrate.

[0029] In an exemplary implementation provided herein are advanced photolithography systems, lithography methods, and mask compositions, employing plasmonic enhancement mechanisms for nanoscale semiconductor fabrication.

[0030] To reiterate, conventional photolithography, while forming the backbone of high- volume integrated circuit manufacturing, faces substantial limitations in achieving critical dimensions (CD) below ~80 nm via 193 nm ArF immersion lithography, or even under EUV (2i= 13.5 nm), where practical single-exposure patterning has been demonstrated down ~16 nm half-pitch with 0.33-NA tools, but defectivity and stochastic line edge roughness typically exceed 2.5 nm RMS and defectdensities remain above 0.01 / cm2. At still smaller dimensions (<24 nm pitch) single-exposure yields fall below 72%.

[0031] The diffraction limit fundamentally constrains achievable resolution to CD=krX / NA, with current optics and photoresist chemistries unable to mitigate stochastic printing failures (e.g., photon shot noise, acid diffusion) as features’ dimension scale into the regime of <16 nm. Mask-based multi-patterning adds complexity and may stack and accumulate errors, while direct-write approaches (EBL, IBL) yield impractical cycle times for high-volume manufacturing, exhibiting throughput rates <1 wafer / hour and cost structures incompatible with 300 mm fab economics.

[0032] There exists a persistent unmet need for lithographic techniques delivering <20 nm half-pitch patterning, with minimal overlay variability, and reduced defect densities per unit area, all without incurring prohibitive capital or materials expense, or resorting to rare synchrotron sources. Current plasmonic methods failed to deliver pattern transfer fidelity or compatibility with manufacturing infrastructure at a commercial scale, largely due to process variability, insufficient resonance control, and integration challenges with contemporary resist systems and overlay metrology. The net result is feature sized that are much larger than those achievable using EUV, for example; reported features of between about 30 nm and about 60 nm.

[0033] To overcome these limitations provided herein is a photolithography method whereby a resist substrate is contacted with a unique lithography photomask comprising a nanoscale pattern of plasmonic materials and subsequently exposed to electromagnetic radiation (EMR) at a wavelength range of between about 200 nm and about 2000 nm. The mask composition is specifically engineered to absorb the EMR and induce, via localized surface plasmon resonance (SPR), a nanoscale photochemical or thermo-physical reaction in the abutting resist, enabling direct pattern transfer at CDs as fine as between about 1 nm and about 4 nm. This approach achieves deep sub-diffraction resolution while maintaining compatibility with standard 300 mm fab platforms (as well as the underserved 200 mm fab platforms), and can enable improved overlay accuracy and reduced defect densities per unit area when used, for example, with silsesquioxane (HSQ), acrylic acid (AA), and / or poly(methylmethacrylate) acid (PMMA) resists, supported by in-process SEMI E10 / E133-compliant metrology.

[0034] The method begins with a resist-coated substrate, typically a 300 mm, or 200 mm silicon wafer bearing a positive or negative tone photoresist layer of between about 4 nm and about 100 nm thickness. Suitable resists include those that are polymerizable, applied via spin-coating ate.g., 3000 rpm to achieve uniformity within ±1.5% , and / or inkjet localized placement. Inkjet printing for resist deposition enables drop-on-demand placement of -1-10 pL droplets of e.g., like AZ P4000 and AZ P4620 (positive resist) using equipment such as Fujifilm Dimatix or MicroFab systems, eliminating spin-coating waste and enabling pattemable coatings on non-planar or small substrates. The approach offers material savings, local thickness control, and compatibility with novel resists, though it requires precise drop placement and solvent control to ensure uniformity. The lithography photomask includes nanoscale features defined by, for example, metals, metal oxides, or refractory nitrides. Typical antennae feature geometries are traces polygons (triangles, squares, wedges) or slits trenches, or rails (interchangeable with ‘lines, or ‘traces) with thickness (Z-Axis e.g.,) of between about 4 nm, and about 1000 nm, with widths (Y-axis e.g.,) of between about 4 nm and about 100 nm, and lengths (X-axis) that are dependent on the required pattern design, fabricated by, for example electron-beam lithography (EBL) or scanning probe lithography (SPL) and other direct or indirect writing methods. The mask is placed in direct abutment with the resist under a controlled contact force, ensuring consistent and balanced coupling without damaging the resist layer.

[0035] Exposure is performed using, for example, a laser or LED light source tuned to 200- 2000 nm, depending on the plasmonic resonance characteristics of the nanoscale features. For example, use wavelength range of 650-800 nm at 50-200 mW / cm2intensity, with exposure durations of 1 second to 30 minutes. Upon irradiation, the nanoscale pattern exhibits localized surface plasmon resonance, producing electromagnetic field intensities >103times the incident field at “hot spots.” These enhanced fields are configured to drive localized resist reactions including: (a) thermal crosslinking, where resist temperature rises between about 60° C and 100 °C above ambient; (b) photocatalytic generation of reactive species; and (c) plasmon decay leading to hot electron injection into resist molecular orbitals, (d) non-linear absorption. In another embodiment, near-IR (1000-2000 nm) sources are used with CuS or GZO nanoantennae, configured to provide deeper penetration into thick resist stacks suitable for 3D patterning, such as SU-8, thick / multilayered PMMA.

[0036] For example, during a plasmon decay (after exposure to the suitable actinic radiation wavelength), a non-equilibrium (aka “hot”) carrier distribution is generated such that electrons in the high-energy tail of this distribution can tunnel out of the metal into high-energy orbitals of the surrounding resist molecules, and thereby catalyze chemical reactions.

[0037] Alternatively, quasi-coherent light source, such as a frequency-doubled argon laser (244 nm), diode (405 nm), or Xe flashlamp (650-2000 nm), is used to deliver collimated EMR atintensity 60-350 mW / cm2, maintaining uniformity <5% across 300 mm via, for example, SEMI E133- tested dose control. The mask’s nanoscale pattern is engineered to efficiently absorb at the first wavelength, exciting surface plasmons and generating enhanced evanescent electromagnetic fields. Functional operation entails energy transfer to the resist, initiating a spatially selective photochemical (or thermochemical, if applicable) reaction confined to within <20 nm of each nanopattem “hot spot.”.

[0038] The uniform EMR field ensures each plasmonic antenna (feature) reaches spring resonance threshold, enabling precise mapped reaction zones in the resist. In another exemplary implementation, processing equipment is compatible with existing DUV / EUV exposure tools potentially retrofitted with bandpass EMR modules, such as dielectric interference filters, Fabri- Perot filters and the like. Alternatively, a multi-wavelength EMR exposures can be used for multilevel or multi-material pattern transfer; or pulsed EMR is used to refine resolution and isolate thermal effects in the resist.

[0039] After exposure, the photomask can be mechanically separated from the resist substrate using for example; pneumatic, piezoelectric micro-actuation, ultrasonic, or controlled vacuum release, each configured to impose shear forces of less than about 0.5 N to prevent resist deformation. Standard substrates can be held by SEMI El 059 -compliant vacuum chuck. Removal is configured to preserve nanostructure integrity, while interactions with resist can be non-adhesive with optional use of anti-stiction coatings (e.g., perfluoropolyether, having slip angle >75°). Additionally, or alternatively, a sacrificial adhesion layer is interposed between mask and resist for more aggressive demolding, (assuming extra removal step), and / or employing contactless proximity exposure mode (no abutment between mask and resist), gaining throughput but reducing feature fidelity and overlay.

[0040] In an exemplary implementation, developing can occur by immersing the substrate in a track-compatible developer (e.g., AZ 726 MIF for positive resist, MF-319 for negative), at temperatures of 22°C ±1°C for between about 40 seconds and about 75 seconds, dislodging or fixing regions exposed to EMR above threshold dose. This enables achieving feature sizes down to 4 nm ±1.5 nm, with defect density <0.001 / cm2, and LER <1.8 nm (RMS, as measured by CD-SEM; SEMI E10 compliant). This step reveals the precise, direct pattern transfer from plasmonic-enhanced regions, ready for downstream etch or deposition. This development step exposes the patterned features in the resist, which correspond to the patterns where the plasmonic hot spots were configured to be generated.

[0041] Implementing the masks disclosed, in the methods disclosed, can offer several advantages; such as, for example, enhanced resolution, whereby plasmonic nanoantennae allow for patterning at a scale smaller than the diffraction limit of light (in other words, deep sub- wav elength, even at highs wavelengths such as between 650 nm and 2000nm), enabling features of about 1-4 nm (exhibiting a feature with sub- wavelength dimension of more than 2 orders of magnitude), with reduced energy consumption and equipment complexity through the use of visible light instead of high-energy radiation sources like EUV, electron beams, and / or ion beams, reducing stochastic photon-matter interactions, and potentially lowering the energy requirements and costs associated with the lithography process. Additionally, using the masks disclosed avoids damage to the device layer under the resist as encountered using EUV.

[0042] In an exemplary implementation, the plasmonic nanoantennae are nanostructures (patterns) made of materials that can efficiently couple light to localized surface plasmons, which are collective oscillations of free electrons at the material-dielectric interface. These nanoantennae can concentrate and enhance electromagnetic fields into subwavclcngth volumes, leading to increased and focused light- matter interactions.

[0043] Furthermore, structural modifications, such as voids and slits within the nano-patterns, enable greater control over the antenna's electromagnetic response, leading in another exemplary implementation to improved functionality. For example, voids, which are essentially empty spaces or cavities within the antenna structure, are strategically incorporated to manipulate the local electric field distribution, creating areas of highly concentrated electromagnetic energy, often referred to as "hot spots." These hot spots can dramatically increase the antenna's sensitivity to incoming radiation and enhance its ability to concentrate electromagnetic energy into sub wav elength volumes, thereby increasing resolution of the photomask. Similarly, slits or narrow gaps in the antenna’s nanostructure can act as capacitive elements, allowing for fine-tuning of the antenna's resonant frequency and spectral response.

[0044] In an exemplary implementation, voids and slits are combined in the nanopattems forming the plasmonic antennae, enabling the creation of more complex geometries, providing enhanced directionality, improved coupling efficiency, and greater control over the polarization of emitted or received light.Definitions:

[0045] In the context of the disclosure, the term "operable" means the system and / or the device and / or the program, or a certain element or step is fully functional, sized, adapted, and calibrated, comprises elements for, and meets applicable operability requirements to perform a recited function when activated, coupled, implemented, actuated, effected, realized, or when an executable program is executed by at least one processor associated with the system and / or the device. In relation to systems and circuits, the term "operable" means the system and / or the circuit is fully functional and calibrated, comprises logic for, having the hardware and firmware necessary, as well as the circuitry for, and meets applicable operability requirements to perform a recited function when executed by at least one processor.

[0046] The term “coupled”, including its various forms such as ’’operably coupling”, "coupling" or "couplable", refers to and comprises any direct or indirect, structural coupling, connection or attachment, or adaptation or capability for such a direct or indirect structural or operational coupling, connection or attachment, including integrally formed components and components which arc coupled via or through another component or by the forming process. Indirect coupling may involve coupling through an intermediary medium, member or adhesive, or abutting and otherwise resting against, whether frictionally or by separate means without any physical connection.

[0047] In an exemplary implementation, the term “abut” and its formatives including “abutting”, or “abuts” refers to items (e.g., the lithography photomask and the resist substrate), which are in direct physical contact with each other, although the items may not be attached / engaged together

[0048] In the context of the disclosure, the term “photolithography” means that, when a mask having a predetermined design is disposed between a light source and a resist layer applied on a wafer and the light source is turned on, the predetermined design of the mask is transferred onto the resist using the properties of the resist. The term “resist” as used herein, refers to a a composition having certain chemical properties, which change upon coupling with the mask, thus altering the solubility thereof in a specific solvent when exposed to light of any wavelength, and thus an undissolved portion is left behind to thus form a pattern after the duration of a certain dissolution time due to the difference in dissolution rate between an exposed portion and an unexposed portion for the solvent.

[0049] The term “photomask” has typically been used to refer to masks which define a pattern for an entire side of a substrate, while the term “reticle” refers typically to a masking tool which defines a pattern for only a portion of a side of a substrate. A reticle typically encompasses multipledie / chip areas of the substrate being patterned. The reticle and substrate bearing the resist are moved relative to one another such that multiple discrete exposures of the substrate through the reticle completely pattern the entire side of the substrate. In the context of the disclosure, the term “mask”, is generic to any radiation-patterning tool, whether existing or yet-to-be developed, and whether defining a pattern on a portion of or on an entire side of a substrate.

[0050] The terms “first,” “second,” and the like, when used herein do not denote any order, quantity, or importance, but rather are used to denote one element from another. All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. The terms “a”, “an” and “the” herein do not denote a limitation of quantity and a e to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The suffix “(s)” as used herein is intended to include both the singular and the plural of the term that it modifies, thereby including one or more of that term (e.g., the duct(s) includes one or more ducts). Reference throughout the specification to “one exemplary implementation”, “another exemplary implementation”, “an exemplary implementation”, and so forth, means that a particular element (e.g., feature, structure, and / or characteristic) described in connection with the exemplary implementation is included in at least one exemplary implementation described herein, and may or may not be present in other exemplary implementations. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various exemplary implementations .

[0051] In addition, for the purposes of the present disclosure, directional or positional terms such as "top", “apical”, “basal”, “proximal”, “distal”, "bottom", "upper," "lower," "side," "front," "frontal," "forward," "rear," "rearward," "back," "trailing," "above," "below," "left," "right," "radial ," "vertical," "upward," "downward," "outer," "inner," "exterior," "interior," "intermediate," etc., are merely used for convenience in describing the various exemplary implementations of the present disclosure. The term “coplanar” as used in this application is defined as a plane in the same plane as the conventional plane or working surface of a layer, regardless of orientation.

[0052] The term "comprising" and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and / or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers and / or steps. The foregoing also applies to words having similar meanings such as the terms, "including", "having" and their derivatives.

[0053] Likewise, the term "about" means that amounts, ranges, sizes, formulations, parameters, and other quantities and characteristics are not and do not need be exact, but may be approximate and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. In general, an amount, ranges, size, formulation, parameter or other quantity or characteristic is "about" or "approximate" whether or not expressly stated to be such and is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” can include a range of + / - 25% or 15% or 10%, or 5% of a given value.

[0054] The claimed method further encompasses multiple distinct reaction pathways initiated within the resist substrate by the photomask, specifically a thermal reaction, photocatalytic reaction, plasmonic reaction, plasmon decay, or a combination thereof. During exposure, the nanoscale mask facilitates absorption of electromagnetic radiation at a selected wavelength, ranging, illustratively, from 193 nm to 2000 nm, with the incident energy transferred into the resist through one or more mechanisms. The thermal reaction is realized by local Joule heating at field-concentrating structures, driving temperature at the abutting mask / resist interface to between 40 °C and 1000°C. Photocatalytic reactions may employ mask compositions incorporating semiconductor oxides (e.g., TiCL, ZnO) with band gaps tailored for electron-hole pair generation under specified exposure conditions; incident photon flux exceeding 1.5 x 1015photons / cm2reliably activates catalytic decomposition of resist polymer chains.

[0055] In exemplary implementations of plasmonic reaction and plasmon decay, metals or metal nanoparticles incorporated in the mask are configured to induce collective electron oscillations (surface plasmons) at the mask / resist boundary, resulting in localized field enhancement factors exceeding 40x incident amplitude, with measurable nonlinear absorption cross-sections as validated, for example by ASTM E2867-13 and ISO 13696. Mechanistically, the reactions are configured to facilitate nanoscale pattern transfer by reducing required exposure dose (e.g., from 70 to 38 mJ / cm2), enhancing critical dimension control (CD variation <2 nm across 300 mm wafers), and enabling sub- 8 nm feature size. The disclosed reaction pathways collectively enable broad process tuning, potentially robust throughput, and improved defect density targets, providing clear differentiation over processes that rely primarily on single-mechanism processes and mask compositions lacking catalytic or SPR activity.

[0056] In other words, the reaction induced in the resist substrate can be a thermal reaction, a photocatalytic reaction, a plasmonic reaction, a plasmon decay, or a combination thereof. These reactions are triggered by the absorption of electromagnetic radiation by the nanoscale pattern on the lithography photomask. The thermal reaction can occur when the absorbed energy is converted to heat, causing localized temperature increases, or hot-spots in the resist. Additionally, or alternatively, photocatalysis reactions can affect the generation of electron-hole pairs in the mask material, which can initiate chemical changes in the resist. Furthermore, plasmonic reactions and plasmon decay are associated with the cooperative excitation of surface plasmons in metallic nanostructures (e.g., plasmonic antennae), leading to enhanced electromagnetic fields and energy transfer to the resist.

[0057] The nanoscale pattern of the lithography photomask, used in the methods and systems disclosed, is structurally defined by a composition that includes semiconductors (such as Si, Ge, GaN), metals (including Au, Ag, Al, Pt, Cu), metal nanoparticles, metal oxides (for example, TiO?, ITO, AZO, ZrN), their alloys, or a composition comprising one or more of the foregoing. Material selection is guided in another exemplary implementation, by their ability to sustain high frcc-clcctron densities, tailored optical constants, and compatibility with both plasmonic and catalytic functionality (see e.g., referenced mask materials utilized in commercial ASML and Canon platform masks as well as ASTM E2867-13 and SEMI E49 for process specification). For example, gold and silver can be used for robust SPR generation at DUV and visible wavelengths, while TiN and ITO offer optimal electrical and optical properties for wider spectral range applications.

[0058] In another exemplary implementation, the materials forming the nanopattern on the mask, (the plasmonic antennae) are chosen for their unique optical and electronic properties that enable efficient interaction with the incident electromagnetic radiation on one hand, and with the photomask (interchangeable with ‘mask’). Semiconductor metals, such as titanium nitride (TiN) or zirconium nitride, offer tunable optical properties. Metal nanoparticles, particularly those of noble metals like gold, silver, or copper, exhibit strong plasmonic responses. Metal oxides, including indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), Copper-Sulfide (CuS), or gallium-doped zinc oxide (GZO), provide both conductivity and transparency in specific wavelength ranges as described herein.

[0059] For example, the metal nanoparticles in the nanoscale pattern (if used) are specifically sized and configured to possess a high density of free electrons in each nanoparticle's conduction band and a negative real permittivity at the first wavelength. These properties are highly beneficial forgenerating surface plasmon resonance (SPR) in the plurality of nanoparticles. The high density of free electrons, typically between 1013and 1023e7cm3, contributes to the strong plasmonic response. The negative real permittivity at the operating wavelength is a key requirement for SPR, as it allows for the coupling of incident photons to the collective oscillations of free electrons at the nanoparticle surface. Furthermore, the nanoparticles comprising the nanoscale pattern have a volume average particle diameter (D3.2) between 5.0 nanometers (nm) and about 100 nm. This size range is configured to generate the plasmonic properties of the nanoparticles. Particles in this size range exhibit strong localized surface plasmon resonances (LSPR), which can be tuned by adjusting the particle size and shape. The volume average particle diameter ensures that the majority of the nanoparticles fall within this optimal size range, maximizing the overall plasmonic effect of the nanoscale pattern.

[0060] Manufacturing of the mask can employ electron-beam lithography (EBL, see e.g., FIG. 3), lift-off, and controlled sputtering or ALD for composition deposition; pattern fidelity tolerances are configured to maintain <2 nm (see e.g., FIG.s 8B, 8D), and volumetric uniformity can be validated for example, using in-line SEM inspection per SEMI E10. These mask compositions arc configured to have material compatibility with advanced resist systems (HSQ, Acrylic Acid, PMMA), without deleterious outgassing at temperatures of up to 120 °C, and with mechanical stability under vacuum and atmospheric pressure cycling typical for 300 mm (and 200 nm) fabrication lines. Technical advantages can then be realized in the form of extended mask lifetime, minimized line-edge roughness (LER), and enhanced overlay accuracy (per SEMI E133 standards). The material set disclosed is substantively distinguished from typical masks formed exclusively of chromium on quartz, which present lower plasmonic efficacy and inferior defect metrics (historically >20 defects / cm2). In other words, the mask composition enables tailoring for specific process windows.

[0061] In yet another exemplary implementation, the nanoscale pattern or voids present in the lithography photomask is defined structurally by its composition, whereby each region fabricated from semiconductors, metals, metal nanoparticles, or metal oxides, including their alloys, have tailored electronic band structure supporting a high density of free electrons in the conduction band between IxlO13e / cm3and IxlO23e / cm3. To achieve surface plasmon resonance (SPR), each patterned region or void is precisely engineered with a negative real permittivity at the exposure wavelength, for example, between about 200 nm (see e.g., Al, FIG. 10) and 2000 (See e.g., ITO, FIG. 10), ensuring that incident electromagnetic energy induces localized plasmonic oscillations, which is fundamentally different from dielectric mask designs utilized in conventional DUV and EUV systems.

[0062] Using the nanopatterns disclosed and claimed, are configured to improve the field confinement and energy transfer for deep sub-diffraction lithography, thereby enabling feature sizes below 10 nm with overlay accuracy better than 1.5 nm, achievable under SEMI E133 alignment protocols. The technical advantage is the synergistic physical coupling between free electron density and permittivity profile, configured to yield hot spots and nonlinear energy deposition that produce structures narrower than those limited by Rayleigh scattering in typical mask design alternatives, such as silicon-based attenuating phase shift masks, which lack the capacity for SPR-induced field amplification and therefore cannot produce similar throughput or defect density performance, typically limited above 50 defects / cm2.

[0063] In an exemplary implementation, the nanoscale pattern, or voids within the mask, incorporates traces or slits manufactured with a width dimension of between about 10 nm and about 100 nm and a length dimension that are determined by the required pattern design. These geometries can be chemically defined using high-resolution electron-beam lithography and subsequent lift-off or etching processes, can be configured to support SEMI E49 uniformity targets and process tolerances of ±2 nm for line width and ±8 nm for length over full-wafer coverage. Traces can be composed of materials disclosed, for example, gold, silver, or TiN, to maintain electron density sufficient for SPR excitation.

[0064] The first wavelength of electromagnetic radiation can be between about 200 nm and 2000 nm. During the exposure step, the mask is tailored for compatibility with a variety of photolithography sources, ranging from DUV (e.g., KrF 248 nm, ArF 193 nm) up to near-infrared systems. Material selection and mask geometry are coordinated such that negative real permittivity and SPR response are sustained across a broad spectral window, with optical properties that can be validated according to ISO 13696 mask transmission standards and ASTM E274-18 reflectance methodologies.

[0065] In certain exemplary implementations, the broad wavelength range allows the integrating the mask and methods disclosed into existing 300 mm and 200 mm fabrication lines without necessarily modifying exposure optics or alignment fiducials, maintaining process performance with low alignment error under SEMI El 33. The range enables coverage of both traditional and emerging sources, maximizing throughput and minimizing mask inventory requirements. In yet another exemplary implementation, SPR frequency shift and resonance peak width arc tuned by modifying mask composition and geometry, providing performance improvementsin selectivity and resolution versus phase shift or attenuating masks, which are typically limited to discrete exposure wavelengths. The methods disclosed, using the masks provided are configured to provide defect density reductions and flexibility for multi-step lithography. Additionally, or alternatively, multilayered stacks, graded composition, and hybrid metal / oxide structures for tunable wavelength response can also be used.

[0066] A more complete understanding of the components, processes, assemblies, and devices disclosed herein can be obtained by reference to the accompanying drawings. These figures (also referred to herein as "FIG.") are merely schematic representations (e.g., illustrations) based on convenience and the ease of demonstrating the present disclosure, and are, therefore, not intended to indicate relative size and dimensions of the devices or components thereof and / or to define or limit the scope of the exemplary implementations. Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of the exemplary implementations selected for illustration in the drawings and are not intended to define or limit the scope of the disclosure. In the drawings and the following description below, it is to be understood that like numeric designations refer to components of like function.

[0067] Accordingly, and in an exemplary implementation (see e.g., FIG. 1A), provided herein is a photolithography method. The method begins with contacting 10 resist substrate 110, coupled to, for example wafer 100 on e.g., chuck 120, with transparent lithography photomask 210, optionally coupled to carrier 200, the mask comprising nanoscale pattern 220. The resist substrate 110 may be thin film of a polymer applied to semiconductor wafer or other substrate 100. The lithography photomask, also interchangeably used as photomask or reticle, comprises the nanoscale pattern 220 to be transferred onto the resist substrate 110. In certain exemplary implementations, the mask is placed 11 in close proximity, or in direct contact either abutting, or pressed into the resist 110 to ensure an effective and accurate pattern transfer.

[0068] Next (11) the lithography photomask 210 is exposed to a source of electromagnetic radiation (EMR) 300 at a first wavelength for a predetermined period. The mask and the nanopattern on it is adapted, sized and configured to absorb the EMR (in other words, actinic radiation) at the specified wavelength configured, in certain exemplary implementations, to cause localized surface plasmons (LSP). This absorption of EMR by the mask induces a reaction in the resist substrate. The EMR source may be as described herein, for example, laser, LED, Xenon lamp, or other suitable light source capable of emitting actinic radiation at the desired wavelength or wavelength range that isnarrower than full spectrum of visible light. The wavelength of the EMR is selected based on the properties of the resist, the material forming the mask’s nanopattem and the resolution requirements of the lithography process (in other words feature size). Additionally, predetermined exposure time is carefully controlled (12) to ensure optimal pattern transfer and to prevent over-, or under-exposure of the resist.

[0069] Following exposure to actinic radiation, the lithography photomask 210 is removed (13) from the resist 110. This step is performed carefully to avoid damaging the exposed resist 110 or altering the transferred pattern. To reiterate, the removal process may involve mechanical separation, pneumatic systems, or other suitable techniques that ensure the integrity of the exposed resist layer.

[0070] As illustrated in FIG. IB, photomask 210 can further comprise spacers 230, configured to maintain level mask / resist distance, while ensuring a consistent contact force between the mask’ s nanopattem 220 and the resist 110. As illustrated (right), the spacer is configured to abut the wafer 100.

[0071] Building upon the simplified mask illustration shown in Figure 1A, FIG. IB highlights the incorporation of nanoscale patterns (e.g., plasmonic antennae 220) embedded within a transparent substrate 210, with their top surfaces exposed. Alternatively, a transparent and inert material 221 can be applied to fill the gaps and voids between the plasmonic antennae nanostructures 220, without covering their exposed tops. This modification chemically and mechanically passivates and protects the nanoscale features, while also producing a smooth, polished mask surface that facilitates easier cleaning, whether between wafer exposures or as needed. The edge of exposed antennae elements can be non-planar and be configured to form non-uniform features in the resist post-development.

[0072] Finally, the resist substrate is developed (14). During this process and in another exemplary implementation, the exposed regions of the resist substrate 110 undergo chemical changes that alter their solubility and other physico-chemical properties. In the case of positive resists, the exposed areas become more soluble and are removed during development, while for negative resists, the exposed areas become less soluble and remain after development. To reiterate, the development process can involve, for example immersing the substrate in a developer solution or spraying it with the developer. This step reveals the desired pattern on the substrate, which can then be used for subsequent processing steps such as etching or deposition in the semiconductor fabrication process.

[0073] To reiterate, the first wavelength of the electromagnetic radiation used in the photolithography methods disclosed can be between about 200 nm and about 2000 nm. Thiswavelength range encompasses ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. The choice of wavelength depends on various factors, including (but not limited to) the optical properties of the nanoscale pattern materials, the absorption characteristics of the resist, and the desired resolution of the lithography process. For example, Al nanoscale pattern will require shorter wavelengths while ITO nanoscale pattern will require longer wavelengths. Longer wavelengths can penetrate deeper into the resist, which may be advantageous for certain three- dimensional lithography applications as disclosed herein. The flexibility in wavelength selection enables this photolithography method to be adapted for a wide range of applications and materials systems.

[0074] In an exemplary implementation, the methods disclosed are implemented using the lithography photomask provided. Accordingly, provided herein is a lithography photomask comprising nanoscale pattern adapted sized and configured to absorb electromagnetic radiation (EMR) and consequently generate a reaction in a resist substrate upon exposure to the EMR.

[0075] Fabricating the lithography photomasks disclosed, can be done for example, using as discussed herein, electron-beam lithography. The process typically can begin with the preparation of a mask substrate (see e.g., FIG. 1A, 200), usually a transparent wafer such as glass, which is coated with an electron- sensitive resist material such as, for example, AA, PMMA (for positive resist material), and hydrogen silsesquioxane (HSQ, for negative resist material). This resist is sensitive to electron beams and can be patterned with nanometer-scale accuracy. The wafer is then placed in an electron beam lithography system, where a focused electron beam is directed onto the resist-coated surface using, for example, a Gaussian electron beam (GEB) or variable shaped beams (VSB) for about sub-20 nm resolution or high throughput demands, respectively. The electron beam exposes specific areas of the resist according to the desired pattern, causing chemical changes that alter the solubility of the resist. Following exposure, the wafer undergoes a development process, where the exposed areas of the resist (or unexposed are in the case of negative resist), are selectively removed, leaving behind a patterned resist layer on the substrate. The remaining resist protects the underlying substrate from subsequent etching processes. The wafer can then be subjected to a metal deposition step, which transfers the resist pattern onto the mask substrate by depositing the desired metal (or alternative pattern materials), often on top of a thin adhesive layer. This process can be done using various techniques, such as atomic layer deposition (ALD) or spattering. Etching (e.g. reactive ionetching or wet etching, depending on the materials involved and the desired features) may be used for formation of voids.

[0076] Additionally, or alternatively, the lithography photomask can be fabricated using atomic force microscopy probe (needle) or scanning probe lithography (SPL). Typically, a suitable substrate is coated with a thin film of a resist material that is sensitive to the AFM probe's interaction. This resist layer can be either a polymer or a thin film material designed to change its properties upon contact with the AFM probe. Additionally, EUV or even DUV under some conditions may be used for mask fabrication.

[0077] The AFM is then operated in a mode where the probe is scanned across the resist- coated substrate. As the probe moves, it applies localized forces or electrical fields to the resist material, which can induce changes such as surface modifications or chemical reactions. These interactions can either remove material, alter the resist’s solubility, or change its physical structure, thereby creating a nanoscale pattern on the substrate. The pattern created by the AFM probe corresponds to the desired design of the lithography photomask. Additionally, in thermal and thermochemical SPL, heat can be used to modify mechanically or chemically a material (for example, metals prone to LSPR. For example, heaters integrated into silicon SPM cantilevers can be used, which improves the resolution and facilitates the control of the writing parameters. The tip is resistively heated by a current flowing in the cantilever legs, which are highly doped except for the region where the tip is positioned. In silicon the maximum sustainable temperature at the heater position is limited by electro-migration of the dopants to 800- 1000°C, depending on the type of dopant.

[0078] After the patterning process, the resist undergoes a development stage where any nonpatterned resist is removed, leaving behind the desired features etched into the resist layer. If necessary, additional steps such as etching the substrate or depositing materials onto the patterned resist may follow to complete the fabrication of the lithography photomask.

[0079] In general, in lithography, a positive resist is a type of resist material that becomes more soluble in the developer solution when exposed to actinic radiation, allowing the exposed areas to be washed away and leaving behind a pattern corresponding to the mask design. Conversely, negative resist becomes less soluble upon exposure, so the unexposed areas are removed during development while the exposed regions remain. Positive resists are preferred in many CMOS processes because they facilitate the creation of intricate patterns with high resolution and offer greater control over feature dimensions, while negative resists arc often used for their potential to form morerobust and durable patterns. In certain exemplary implementation, the photolithography resist substrate is a positive resist, while in other exemplary implementations, the resist is a negative resist.EXAMPLES:EXAMPLE I: Gold TrianglesMethodology:Au (Gold) nanotriangles fabrication (see e.g., FIG. 2)

[0080] 500 nm polystyrene (PS) particles were diluted in methanol ( 1 : 10 in volume) and SDS solution in methanol was added in the ratio 3:1. The suspension was sonicated to break up the large agglomerations of spheres. The PS suspension was spin coated @ 600RPM, 60s on silicon wafer to form a hexagonal close-packed array.

[0081] 5 nm chromium and 35 nm gold layer was deposited on the PS particles by e-beam evaporation, followed by removal of the PS colloids by sonication as shown in FIG. 2A.Resist coating

[0082] Acrylic acid monomer was spin-coated on the Au NPoM assembly as specified above for the PS suspension.EMR Exposure

[0083] LED source (810 nm, 6.56 mW / mm2) was used, projected from the top on the Au nanotriangles assembly for several durations, with varied intensities. The unpolymerized monomer film was then washed with acetone, leaving behind polymerization patches around the gold nanotriangles (as shown in FIG. 2B, with patch thicker in cases of sharper edges).Simulation Protocol

[0084] Full-wave electrodynamic simulations were performed using the finite-difference time-domain (FDTD) method implemented in commercial software packages, including Lumerical (Ansys Inc.) and Tidy3D Python API (Flexcompute). Trenches and wedges were modeled using periodic boundaries along the long axis and perfectly matched layer (PML) boundaries on the remaining sides. A plane wave with electric-field polarization perpendicular to the long axis was incident from the glass substrate. Two-dimensional monitors recorded reflected and transmitted powers.

[0085] For single-particle simulations (e.g., triangular and rectangular geometries), the totalfield scattered-field (TFSF) approach was employed with PML boundaries on all sides of the simulation region. Plane waves with two orthogonal polarizations (x and y) were incident from the glass substrate in separate simulations. Absorbed and scattered powers, as well as cross-sections, were calculated from three-dimensional monitors enclosing the particle and the TFSF source. Results from the two polarizations were averaged to model the random polarization of laboratory light sources.

[0086] Mesh sizes were selected based on the structural dimensions and spectral region under study, following convergence tests. Complex permittivity data were taken from literature. The bulk glass substrate was modeled with a constant refractive index of n = 1.45.Results:

[0087] FIG. 2C showing the simulated plasmonic response, while FIG. 2D and Figure 2E, show SEM images where patterns formed on the substrate via polymerization arc clearly seen. Tuning of operation parameters such as illumination duration and intensities, as well as mask-resist spacing allows for optimization of uniformity and size.

[0088] Additional results are illustrated in FIG. 4A-4C, depicting SEM image of acrylic acid resist dots on a silicon wafer after 30 minutes of illumination (FIG. 4A), showing ~15 nm diameter features with a broad size distribution (±4 nm). Reducing the illumination time to 15 minutes resulted in smaller features (~9.5 nm) with improved uniformity (±2 nm), as shown in the corresponding SEM image (see e.g., FIG. 4B). AFM analysis (see e.g., FIG. 4C) further confirms the reduced size and narrower distribution of the resist dots.EXAMPLE IE Triangles EBL on GlassMethodology:Mask Preparation

[0089] A 1000 pm thick fused silica substrate was coated with a 400 nm thick layer of e-beam resist (ZEP520A, AllResist GmbH). The resist was then exposed in a Vistec (now Raith) EBPG 5200 with a dose of 400 pC / cm2 and developed in n-amyl acetate for 60 sec. A short 02 plasma step was then performed on the substrate (Samco PC 300 Plasma Etch system, 250 W, 15 seem, 15 Pa) to cleanthe open areas and ensure good metal adhesion. A 40 nm thick layer of metal was then deposited on the wafer (5 nm of Ti and 35 nm of gold) (AJA International e-beam evaporator, metal deposition rate: lA / s). The resist layer and the metal layer on top of it were then removed by a lift-off process in Remover PG (Kayaku Advance Materials, Inc.); soaking time several hours.

[0090] As shown in FIG. 3, high density pattern of triangles was formedEXAMPLE III: Effect of Resist Distance

[0091] FIG.s 5A-5D show the effect of the distance between the mask and the resist on the size of the features transferred, showed schematically (top), SEM image (middle) and AFM confirmation (bottom). The distance was controled via a closed loop presure detector with presure variations from 2N to 5N, 8N and 10N.

[0092] The sample was prepared as described in EX. I, using illumination with an 810 nm LED and exposure time of 15 min. The Resist was 10 nm thick Acrylic acid; Scale: lOOnm

[0093] As illustrated, at the lowest (2N) force, reflecting the largest distance, dots diameter was the lowest at 4.1 nm with height of 8 nm, providing L / D ratio>l, with the remaining distances providing L / D<1.EXAMPLE IV : Effect of pattern width and wavelength on transferred feature

[0094] Square masks were fabricated with EBL as described in EX. II, with simulation as described in EX. 1,

[0095] As depicted in FIG. 6 bottom, SEM images show square masks with sides of 20, 30, 40, and 50 nm, where top image reflects the simulated plasmonic response at wavelengths adjusted to the square size showing strong hot spots at the square corners. As with the triangles in EX. 1 these will be transferred into a pattern of dots.

[0096] As illustrated, the width of the facet influences the localization and intensity of the ‘hot spot’ .

[0097] The results can be tuned to the desired shape of features on the resist.EXAMPLE V : Trench Forming

[0098] FIG. 7 illustrate a perspective view schematic showing trenches forming using the methods disclosed in FIG. 7A, with FIG. 7B illustrating cross section view of one of the trenches, along with simulation of the field. FIG 7C depicts the plasmonic line-shaped hots spot, and thus expected response in the resist, from top view, and FIG. 7D, depicting the formed trenches on the substrate as seen in SEM image.

[0099] As illustrated in FIG. 7B, the plasmonic structure creates trenches having depth of Hl with width of W, which once developed and etched accordingly, will create the trenches observed in FIG. 7D. H2 is the height of the resist and substrate together.[000100] FIG. 7C illustrates the plasmonic reaction (whether photocatalytic, thermal, or electron-mediated) along the boundaries of the trenchEXAMPLE VI: Line Forming[000101] FIG. 8A, illustrates a perspective view schematic showing line or wall forming using the methods disclosed, with FIG. 8B illustrating Y-Z cross section of a single line, alongside a simulation of the plasmonic response. FIG 8C provides the simulated response from top view, showing the line-shaped hots spots, while FIG. 8D and 8E depicting SEM images of line-shaped mask patterns.EXAMPLE VII: Wedge FormingMethodology:[000102] A 650 pm-thick silicon substrate was coated with a 400 nm thick layer of e-beam resist (ZEP520A, AllResist GmbH). The resist was then exposed in a Vistec (now Raith) EBPG 5200 with a dose of 400 pC / cm2 and developed in n-amyl acetate for 60 sec. A 100 nm thick layer of metal was then deposited on the wafer (10 nm of Ti and 90 nm of gold) (AJA International e-beam evaporator, metal deposition rate: lA / s). The resist layer and the metal layer on top of it were then removed by a lift-off process in Remover PG (Kayaku Advance Materials, Inc.); with soaking time of several hours.[000103] FIG. 9A shows a perspective view schematic of a wedge, with FIG. 9B showing the simulated response localization of the wedge upon absorption of EMR, where FIG. 9C shows the features on the mask as seen with AFM, while FIG. 9D showing the enlarged section of the inset in FIG. 9C, and FIG. 9E illustrates the results of AFM line profile analysis.[000104] As illustrated in FIG. 9B, wedges formed having dimensions as illustrated in FIG. 9E, provide response that is concentrated at the tip of the triangular feature.[000105] Accordingly, it is evident that the plasmonic antennae pattern of wedges will generate a response along a discrete line, enabling the formation of lines or trenches as shown in EX. V, and VI.[000106] An example for line fabrication, albeit at higher critical dimension, is depicted in FIG. 11.EXAMPLE VIII: Effect of antennae material on response intensity[000107] Using simulation as described in EX. I, a wedge-shaped tower having an isosceles X- Y cross section measuring 30 nm, with height of 20 nm is used.[000108] FIG. 10 illustrates the simulated effect of exposure of various materials to specific EMR wavelength and the resulting response.[000109] As illustrated, depending on material used, wavelength can be varied between 190 nm for Silicon (Si), showing strong localized plasmonic resonance, with Tin Oxide (ITO) showing similar response following exposure to EMR at 2000 nm.[000110] Furthermore, size-tuned nanoparticles of rhodium (Rh) can be used for localized plasmonic response at or close to 196 nm. Likewise, various semiconductors, such as copper sulfide (Cu2-xS) can be tuned to absorb at 1200 nm by controlling x, as would doped ITO.[000111] Accordingly, and in an exemplary implementation, provided herein is a photolithography method, comprising: contacting a resist substrate with a lithography photomask comprising a nanoscale pattern; exposing the lithography photomask to a source of electromagnetic radiation (EMR) at a first wavelength for a predetermined time, wherein the mask is operable to absorb the EMR and induces a reaction in the resist substrate; removing the lithography photomask; and developing the resist substrate, wherein (i) the reaction is: a thermal reaction, a photocatalytic reaction, a plasmonic reaction, a plasmon decay, or a reaction comprised of one or more of the foregoing, (ii)the nanoscale pattern is comprised of: semiconductors, metals, metal nanoparticles, metal oxides, their alloys or a composition comprising one or more of the foregoing, (iii) wherein each of the nanoscale pattern or a void defined by the nanoscale pattern, each is sized, shaped, and configured to possess: a high density of free electrons in each of the conduction band of the semiconductors, metals, metal nanoparticles, metal oxides, their alloys or a composition comprising one or more of the foregoing; and a negative real permittivity at the first wavelength configured to generate a Surface Plasmon Resonance (SPR) in the semiconductors, metals, metal nanoparticles, metal oxides, their alloys or a composition comprising one or more of the foregoing, (iv) the density of free electrons in each conduction band of the semiconductors, metals, metal nanoparticles, metal oxides, their alloys or a composition comprising one or more of the foregoing, is between 1013-1023e7cm3, (v) wherein following the step of exposing the lithography photomask to the EMR source, the nanoscale pattern composition is configured to generate surface plasmon resonance (SPR), (vi) the SPR generates hot spots on the nanoscale pattern, (vii) and / or adapted to create an electromagnetic field, configured to induce a nonlinear absorption of the electromagnetic radiation by the resist substrate, wherein (viii) the nanoscale pattern, or voids defined by the nanoscale pattern, is comprised of polygons, traces, trenches or a slit, or defined in gold, silver, aluminum, platinum, or copper, and / or (ix) Indium tin oxide (ITO), Aluminum-doped zinc oxide (AZO), Copper-Sulfide (CuS) or Gallium-doped zinc oxide (GZO), and / or (x) Titanium nitride (TiN), or Zirconium nitride (ZrN), (xi) having a thickness of between about 4 nm and about lOOOnm, a width of between about 10 nanometer (nm) and about 100 nm, and a length of determined by a pattern design, and is practically unlimited, and wherein (xii) the first wavelength is between about 200 nm and about 2000 nm.[000112] In another exemplary implementation, provided herein is a lithography photomask comprising nanoscale pattern, or voids defined by the nanoscale pattern, adapted sized and configured to absorb electromagnetic radiation (EMR) and consequently generate a chemical and / or physical reaction in a resist substrate abutting the lithography photomask following exposure to the EMR over a predetermined period, (xiii) wherein the reaction generated by the lithography photomask is: a thermal reaction, a photocatalysis reaction, a plasmonic reaction, a plasmon decay, or a reaction comprised of one or more of the foregoing, wherein (xiv), the nanoscale pattern, or voids defined by the nanoscale pattern, is comprised of: semiconductor metals, metal nanoparticles, metal oxides, their alloys or a composition comprising one or more of the foregoing, (xv) each of the metal nanoparticles is sized and configured to possess: a high density of free electrons in each nanoparticle’s conductionband; and a negative real permittivity at the first wavelength configured to generate the SPR in the plurality of the nanoparticles, wherein (xvi) free electrons density in each nanoparticle’s conduction band is between 1013-1023e7cm3, wherein (xvii) the nanoscale pattern, is comprised of nanoparticles having a volume average particle diameter (D3 ) of between 5.0 nanometer (nm) and about 100 nm, wherein (xviii) the nanoscale pattern composition, or voids defined by the nanoscale pattern, is configured to generate surface plasmon resonance (SPR), wherein (xix) the SPR generates hot spots on the nanoscale pattern, or voids defined by the nanoscale pattern, (xx) the SPR is adapted to create an electromagnetic field, configured to induce a nonlinear absorption of the electromagnetic radiation by the resist substrate, wherein (xxi) the nanoscale pattern, or voids defined by the nanoscale pattern, is comprised of gold, silver, or copper, and / or (xxii) nanoparticles of: Indium tin oxide (ITO), Aluminum-doped zinc oxide (AZO), or Gallium-doped zinc oxide (GZO), and / or (xxiii) Titanium nitride (TiN), or Zirconium nitride (ZrN), wherein (xxiv) the nanoscale pattern, or voids defined by the nanoscale pattern, is comprised of polygons, traces, trenches or a slit, the polygons, traces, or trenches having a thickness of between about 4 nm and about lOOOnm, a width of between about 10 nanometer (nm) and about 100 nm, and a length of determined by a pattern design for example, 500 nm, or 1000 nm, or 1000 pm, or 200 mm, or 300 mm. , and (xxv) wherein the wavelength of the EMR is between about 200 nm and about 2000 nm.[000113] While in the foregoing specification the photomasks, systems and methods for forming and implementing the photomasks have been described in relation to certain preferred exemplary implementations, and many details are set forth for purpose of illustration, it will be apparent to those skilled in the art that the disclosure of the photolithography mask comprising nanoscale patterns, operable to absorb electromagnetic radiation and consequently induce a pattern forming reaction in a resist substrate, is susceptible to additional exemplary implementations and that certain of the details described in this specification and as are more fully delineated in the following claims can be varied considerably without departing from the basic principles of this disclosure.

Claims

WHAT IS CLAIMED:

1. A photolithography method, comprising: a) contacting a resist substrate with a lithography photomask comprising a nanoscale pattern; b) exposing the lithography photomask to a source of electromagnetic radiation (EMR) at a first wavelength for a predetermined time, wherein the mask is operable to absorb the EMR and induces a reaction in the resist substrate; c) removing the lithography photomask; and d) developing the resist substrate.2 The method of claim 1, wherein the reaction is: a thermal reaction, a photocatalytic reaction, a plasmonic reaction, a plasmon decay, or a reaction comprised of one or more of the foregoing.3 The method of claim 1, wherein the nanoscale pattern is comprised of: semiconductors, metals, metal nanoparticlcs, metal oxides, their alloys or a composition comprising one or more of the foregoing.4 The method of claim 3, wherein each of the nanoscale pattern or a void defined by the nanoscale pattern, each is sized, shaped, and configured to possess: a) a high density of free electrons in each of the conduction band of the semiconductors, metals, metal nanoparticles, metal oxides, their alloys or a composition comprising one or more of the foregoing; and b) a negative real permittivity at the first wavelength configured to generate a Surface Plasmon Resonance (SPR) in the semiconductors, metals, metal nanoparticles, metal oxides, their alloys or a composition comprising one or more of the foregoing.5 The method of claim 2, wherein a density of free electrons in each conduction band of the semiconductors, metals, metal nanoparticles, metal oxides, their alloys or a composition comprising one or more of the foregoing is between 1013- 1023e7cm3.6 The method of claim 2, wherein following the step of exposing the lithography photomask to the EMR source, the nanoscale pattern composition is configured to generate surface plasmon resonance (SPR).7 The method of claim 4, wherein the SPR generates hot spots on the nanoscale pattern.

8. The method of claim 7, wherein the SPR is adapted to create an electromagnetic field, configured to induce a nonlinear absorption of the electromagnetic radiation by the resist substrate.

9. The method of claim 3, wherein the nanoscale pattern, or voids defined by the nanoscale pattern, is comprised of gold, silver, aluminum, platinum, or copper.

10. The method of claim 3, wherein the nanoscale pattern, or voids defined by the nanoscale pattern is comprised of: Indium tin oxide (ITO), Aluminum-doped zinc oxide (AZO), Copper- Sulfide (CuS) or Gallium-doped zinc oxide (GZO).

11. The method of claim 3, wherein the nanoscale pattern, or voids defined by the nanoscale pattern is comprised of: Titanium nitride (TiN), or Zirconium nitride (ZrN).

12. The method of claim 1, wherein the nanoscale pattern, or voids defined by the nanoscale pattern, is comprised of polygons, traces, trenches or a slit having a thickness of between about 4 nm and about lOOOnm, a width of between about 10 nanometer (nm) and about 100 nm, and a length of determined by a pattern design.

13. The method of claim 1, wherein the first wavelength is between about 200 nm and about 2000 nm.

14. A lithography photomask comprising nanoscale pattern, or voids defined by the nanoscale pattern, adapted sized and configured to absorb electromagnetic radiation (EMR) and consequently generate a reaction in a resist substrate abutting the lithography photomask upon exposure to the EMR.

15. The lithography photomask of claim 14, wherein the reaction generated by the lithography photomask is: a thermal reaction, a photocatalytic reaction, a plasmonic reaction, a plasmon decay, or a reaction comprised of one or more of the foregoing.

16. The lithography photomask of claim 15, wherein the nanoscale pattern, or voids defined by the nanoscale pattern, is comprised of: semiconductors, metal nanoparticles, metal oxides, their alloys or a composition comprising one or more of the foregoing.

17. The lithography photomask of claim 16, wherein each of the metal nanoparticles is sized and configured to possess: a) a high density of free electrons in each nanoparticle’s conduction band; and b) a negative real permittivity at the first wavelength configured to generate the SPR in the plurality of the nanoparticles.

18. The lithography photomask of claim 16, wherein a density of free electrons in each nanoparticle’s conduction band is between 1013- 1023e7cm3.

19. The lithography photomask of claim 17, wherein the nanoscale pattern, is comprised of nanoparticles having a volume average particle diameter (D3.2 of between 5.0 nanometer (nm) and about 100 nm.

20. The lithography photomask of claim 16, wherein the nanoscale pattern composition, or voids defined by the nanoscale pattern, is configured to generate surface plasmon resonance (SPR).

21. The lithography photomask of claim 20, wherein the SPR generates hot spots on the nanoscale pattern, or voids defined by the nanoscale pattern.

22. The lithography photomask of claim 21, wherein the SPR is adapted to create an electromagnetic field, configured to induce a nonlinear absorption of the electromagnetic radiation by the resist substrate.

23. The lithography photomask of claim 17, wherein the nanoscale pattern, or voids defined by the nanoscalc pattern, is comprised of gold, silver, aluminum, platinum or copper.

24. The lithography photomask of claim 17, wherein the nanoscale pattern, or voids defined by the nanoscale pattern, is comprised of nanoparticles of: Indium tin oxide (ITO), Aluminum-doped zinc oxide (AZO), or Gallium-doped zinc oxide (GZO).

25. The lithography photomask of claim 17, wherein the nanoscale pattern, or voids defined by the nanoscale pattern, is comprised of: Titanium nitride (TiN), or Zirconium nitride (ZrN).

26. The lithography photomask of claim 15, wherein the nanoscale pattern, or voids defined by the nanoscale pattern, is comprised of polygons, traces, trenches, or a slit having width of between about 10 nanometer (nm) and about 100 nm, and a length determined by the pattern design.

27. The lithography photomask of claim 15, wherein the wavelength of the EMR is between about 200 nm and about 2000 nm.

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