Classifications

• • 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
  • G03F7/0035—Multiple processes, e.g. applying a further resist layer on an already in a previously step, processed pattern or textured surface
• • 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
  • G03F7/09—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers
  • G03F7/11—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers having cover layers or intermediate layers, e.g. subbing layers
• • 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
  • G03F7/40—Treatment after imagewise removal, e.g. baking
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
  • H10P50/69—Etching of wafers, substrates or parts of devices using masks for semiconductor materials
  • H10P50/691—Etching of wafers, substrates or parts of devices using masks for semiconductor materials for Group V materials or Group III-V materials
  • H10P50/693—Etching of wafers, substrates or parts of devices using masks for semiconductor materials for Group V materials or Group III-V materials characterised by their size, orientation, disposition, behaviour or shape, in horizontal or vertical plane
  • H10P50/695—Etching of wafers, substrates or parts of devices using masks for semiconductor materials for Group V materials or Group III-V materials characterised by their size, orientation, disposition, behaviour or shape, in horizontal or vertical plane characterised by the process involved to create the mask, e.g. lift-off masks or sidewalls or to modify the mask
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P76/00—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography
  • H10P76/20—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography of masks comprising organic materials
  • H10P76/204—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography of masks comprising organic materials of organic photoresist masks
  • H10P76/2041—Photolithographic processes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P76/00—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography
  • H10P76/40—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography of masks comprising inorganic materials
  • H10P76/408—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography of masks comprising inorganic materials characterised by their sizes, orientations, dispositions, behaviours or shapes
  • H10P76/4085—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography of masks comprising inorganic materials characterised by their sizes, orientations, dispositions, behaviours or shapes characterised by the processes involved to create the masks
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P76/00—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography
  • H10P76/40—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography of masks comprising inorganic materials
  • H10P76/408—Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography of masks comprising inorganic materials characterised by their sizes, orientations, dispositions, behaviours or shapes
  • H10P76/4088—Processes for improving the resolution of the masks

Definitions

• This invention relates to microfabrication including microfabrication of integrated circuits as well as processes involved in patterning semiconductor substrates.
• creating patterned layers typically involves the application of a thin layer of radiation-sensitive material, such as photoresist, to an upper surface of a substrate.
• This radiation-sensitive material is transformed into a patterned mask that can be used to etch or transfer a pattern into an underlying layer on a substrate.
• Patterning of the radiation-sensitive material generally involves exposure by a radiation source through a reticle (and associated optics) onto the radiation-sensitive material using, for example, a photolithographic exposure system. This exposure creates a latent pattern within the radiation-sensitive material which can then be developed.
• Developing refers to dissolving and removing a portion of the radiation-sensitive material to yield a relief pattern (topographic pattern).
• the portion of material removed can be either irradiated regions or non-irradiated regions of the radiation-sensitive material depending on a photoresist tone and/or type of developing solvent used.
• the relief pattern can then function as a mask layer defining a pattern.
• Preparation and development of various films used for patterning can include thermal treatment or baking.
• a newly applied film can receive a post-application bake (PAB) to evaporate solvents and/or to increase structural rigidity or etch resistance.
• a post-exposure bake (PEB) can be executed to set a given pattern to prevent further dissolving.
• Fabrication tools for coating and developing substrates typically include one or more baking modules.
• Some photolithography processes followed by coating with a resist, and then exposing the substrate to a pattern of light as include coating a substrate with a thin film of Bottom Anti -reflective Coating (BARC), followed by coating with a resist, and then exposing the substrate to a pattern of light as a process step for creating microchips.
• a relief pattern created can then be used as a mask or template for additional processing such as transferring the pattern into an underlying layer.
• Anti-spacer is a self-aligned technology that uses the diffusion length of a reactive species to define a critical dimension (CD), creating a narrow trench. With a reactive species controlled spatially via exposure through a mask, then instead of a narrow trench, a narrow slot contact can be formed. A corresponding CD can be tuned through molecular weight modification of the reactive species, molecular structure of the reactive species, and the bake temperature and bake time. These techniques enable access to narrow slot contact features at dimensions beyond the reach of advanced lithographic capabilities. But processing requires a “freeze” step, that is, a treatment that neutralizes a solubility shifting potential of a layer having a photo-acid generator. Freeze processing, however, is not perfect and can reduce throughput. Techniques herein provide a “freeze-less” anti-spacer method that enables accessing narrow slot contacts defined by diffusion lengths. Techniques include inverting a pattern and using compositions resistive to solubility shifts.
• a method of patterning a substrate is provided.
• a first relief pattern that includes openings can be formed based on a first layer deposited over a substrate.
• the openings in the first relief pattern can be filled with a reversal material, where the reversal material can contain a resin and a photo-acid generator.
• the resin can be insoluble to a predetermined developer, and the resin can further be insensitive to a photo-acid generated from the photo-acid generator in that the resin remains insoluble to the predetermined developer when the resin is in contact with the photo-acid.
• the first relief pattern can then be removed from the substrate such that the reversal material remains on the substrate to define a second relief pattern, where the second relief pattern is an inverse pattern of the first relief pattern.
• a fill material can subsequently be deposited over the substrate.
• the fill material can be in contact with the second relief pattern, and sensitive to the photo-acid generated from the photo-acid generator in that portions of the fill material that are in contact with the photo -acid become soluble to the predetermined developer.
• Selected portions of the second relief pattern can be exposed to a first actinic radiation that causes a portion of the photo-acid generator within the selected portions of the second relief pattern to generate the photo-acid in the selected portions of the second relief pattern.
• the photo-acid generated in the selected portion of the second relief pattern can be further driven from the selected portions of the second relief pattern into portions of the fill material through interfaces between the selected portions of the second relief pattern and the fill material. Accordingly, the photo-acid can cause the portions of the fill material to become soluble to the predetermined developer.
• the soluble portions of the fill material can be removed by using the predetermined developer so as to form a third relief pattern.
• the third relief pattern can uncover an underlying layer that is positioned between the substrate and the fill material.
• the third relief pattern can further be transferred into the underlying layer through an etching process.
• the photo-acid in order to drive the photo-acid generated in the selected portion of the second relief pattern from the selected portions of the second relief pattern into the portions of the fill material, the photo-acid can be diffused a predetermined distance into the fill material by a diffusion process through the interfaces between the selected portions of the second relief pattern and the fill material.
• the first layer in order to form the first relief pattern, can be exposed to a second actinic radiation that forms a latent pattern, and the latent pattern can be developed through a developer to form the first relief pattern.
• the first layer can be a layer of photoresist.
• an overburden of the reversal material can be deposited and the overburden of the reversal material can further be removed.
• the fill material can be free of the photo-acid generator.
• a thermally activated diffusion process can be applied to drive the photo-acid.
• the thermally activated diffusion process can include heating the substrate at a predetermined temperature for a predetermined duration.
• the fill material can include a de-protection group that causes the fill material to become soluble in a presence of the photo-acid.
• a method of patterning a substrate is provided.
• a first relief pattern that includes openings can be formed based on a first layer deposited over a substrate.
• the openings in the first relief pattern can be filled with a reversal material, where the reversal material can contain a resin and a generator compound that generates a solubility-changing agent in response to exposure to an actinic radiation.
• the resin can be insoluble to a predetermined developer, and further be insensitive to the solubility-changing agent in that the resin remains insoluble to the predetermined developer when the resin is in contact with the solubility-changing agent.
• the first relief pattern can then be removed from the substrate such that the reversal material remains on the substrate to define a second relief pattern, where the second relief pattern can be an inverse pattern of the first relief pattern.
• a fill material can be deposited on the substrate, where the fill material can be in contact with the second relief pattern, and sensitive to the solubility-changing agent generated from the generator compound in that portions of the fill material that are in contact with the solubility changing agent become soluble to the predetermined developer.
• Selected portions of the second relief pattern can be exposed to an actinic radiation that causes a portion of the generator compound within the selected portions of the second relief pattern to generate the solubility-changing agent in the selected portion of the second relief pattern.
• the solubility-changing agent generated in the selected portions of the second relief pattern to can be driven to diffuse from the selected portions of the second relief pattern into portions of the fill material through interfaces between the selected portions of the second relief pattern and the fill material.
• the solubility changing agent can cause the portions of the fill material to become soluble to the predetermined developer.
• the solubility-changing agent can include a photo-acid.
• the solubility-changing agent can include a photo destructive base.
• the generator compound can be a photo acid generator (PAG) that generates the photo-acid in response to exposure to the first actinic radiation.
• PAG photo acid generator
• the generator compound can be a photo destructive base generator that generates the photo destructive base in response to exposure to the first actinic radiation.
• a thermally activated diffusion process in order to drive the solubility-changing agent generated in the selected portions of the second relief pattern to diffuse from the selected portions of the second relief pattern into the portions of the fill material, a thermally activated diffusion process can be applied by controlling an average diffusion length of the solubility-changing agent.
• the generator compound includes a thermal acid generator (TAG), where the thermal acid generator can include sulfonate esters that are derived from oximes, imides and benzyl alcohols.
• TAG thermal acid generator
• the fill material can be free of the generator compound.
• FIGS. 1A, IB, 2A, 2B, 3A, 3B, 4A, 4B, 5A, 5B, 6A, 6B, 7A, 7B, 8A, 8B, 9A, and 9B are cross-sectional and top down views of intermediate steps of manufacturing narrow slot contacts, in accordance with some embodiments.
• spatially relative terms such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures.
• the spatially relative terms are intended to encompass different orientations of the apparatus in use or operation in addition to the orientation depicted in the figures.
• the apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
• Techniques herein provide a “freeze-less” anti-spacer method that enables accessing narrow slot contacts defined by diffusion lengths.
• Techniques include inverting a pattern and using compositions resistive to solubility shifts.
• Description of example embodiments herein can use a photo-acid as reactive species.
• solubility-shifting agents can also be used, such as a photo-destructive base.
• FIGS. 1 A, 2A, 3A, 4A, 5A, 6A, 7A, 8A, and 9A are cross-sectional views of intermediate steps of manufacturing narrow slot contacts.
• FIGS. IB, 2B, 3B, 4B, 5B, 6B, 7B, 8B, and 9B are top down views of the intermediate steps of manufacturing the narrow slot contacts. The cross-sectional views are obtained from a plane same as a vertical plane containing line A-A’ in the top down views.
• FIG. 1 A shows cross-sectional view and FIG. IB shows a top down view of an example substrate segment 100 being exposed to an actinic radiation 110 through a photomask 108 to create a latent pattern 112 in a first layer 106.
• the first layer 106 ca be formed of a photoresist material or other photo-sensitive materials.
• the substrate segment 100 can include a substrate 102, a dielectric layer (or underlying layer) 104 over the substrate 102, and the first layer 106 positioned over the dielectric layer 104.
• the substrate 102 can be a semiconductor substrate such as Si substrate.
• the substrate 102 may also include other semiconductors such as germanium (Ge), silicon carbide (SiC), silicon germanium (SiGe), or diamond. Alternately, the substrate 102 may include a compound semiconductor and/or an alloy semiconductor.
• the dielectric layer 104 can include SiO, SiN, SiCN, SiON, or other suitable dielectric materials. In some embodiments, the dielectric layer 104 can be a dielectric stack that includes one or more dielectric layers.
• the first layer 106 that is a photoresist may be composed of a non-chemically amplified system such as a diazonaphthoquinone dissolution inhibitor and a Novolak polymer.
• exposed portions (e.g. the latent pattern 112) of the first layer 106 can become soluble to a particular developer.
• the actinic radiation 110 can cause the exposed portions of the first layer 106 to become insoluble depending on a material type (or a tone) of the first layer 106, and a material type (or a tone) of the corresponding developer.
• FIGS. 2 A and 2B illustrate a result after a develop step is executed.
• developing chemicals in the particular developer can be applied to dissolve the exposed regions (e.g., the latent pattern 112) of the first layer 106 so that the exposed regions can be washed away from the substrate segment 100.
• a first relief pattern or topographical pattern 202 can be formed over the substrate 102.
• the first relief pattern 202 can include raised features 204 covering the underlying layer 104, and openings 206 uncovering other portions of the underlying layer 104.
• the first relief pattern 202 can be formed by a photolithography process or other means as mentioned above.
• the openings 206 of the first relief pattern 202 in the illustrated substrate segment 100 can have a trench profile.
• the openings 206 can be trenches, slots, holes, or any shape according to the structures of the contacts.
• a reversal material 302 can be filled in the openings 206 of the first relief pattern 202.
• the reversal material 302 can contain a resin and a generator compound, such as a photo-acid generator.
• the resin can be selected to be insensitive (with respect to solubility) to a photo-acid generated by the photo-acid generator and insoluble to one or more particular developers.
• the reversal material 302 can be free from functional groups that would cause a solubility shift from the photo-acid, or include functional groups to prevent a solubility-shift, depending on tone scheme.
• the resin can be a co- or ter-polymer composed of monomers including but not limited to styryl groups, low molecular weight acrylates such as methacrylic acid, methyl methacrylate and tert-butyl acrylate, lactones, norbornene and adamantyl derivates.
• monomers including but not limited to styryl groups, low molecular weight acrylates such as methacrylic acid, methyl methacrylate and tert-butyl acrylate, lactones, norbornene and adamantyl derivates.
• Primary design rules for choice of monomer composition and ratio are casting solvent solubility, developer solubility and etch resistance.
• the generator compound in the reversal material 302 can include a photo acid generator (PAG) that generates a photo-acid in response to exposure to an actinic radiation.
• the generator compound can include a photo destructive base generator that generates the photo destructive base in response to exposure to the actinic radiation.
• the acid source (e.g., the generator compound) in the reversal material 302 can be a thermal acid generator (TAG).
• Typical PAG compositions include iodonium or sulfonium salts with a counterion such as a fluorinated sulfonate or hexafluoroantimonate.
• the structure of the PAG can define a wavelength of an irradiation (e.g., actinic radiation 110) necessary for activation.
• Acid generation from the reversal material 302 can occur by irradiation from a wide array of wavelengths but can be optimally chosen to coincide with the absorption of the resin in the reversal material 302.
• Common TAGs include, but are not limited to, various sulfonate esters that are derived from oximes, imides and benzyl alcohols.
• Deposition of such reversal materials 302 can typically result in an overburden of the reversal material over the first layer 106, especially when the reversal material 302 is deposited by a spin-on deposition.
• the overburden can be removed via any planarization process, such as a chemical mechanical planarization (CMP), a controlled wet etch-back (by using TMAH, for example), and a chemically-amplified planarization using a location- specific top-down acid diffusion in a developer scheme that can cause a shift (i.e., diffusion of the acid, the acid cause the material property changed, and soluble) to being soluble in a planarizing developer scheme.
• CMP chemical mechanical planarization
• TMAH controlled wet etch-back
• a chemically-amplified planarization using a location- specific top-down acid diffusion in a developer scheme that can cause a shift (i.e., diffusion of the acid, the acid cause the material property changed, and soluble) to being
• FIGS. 3A and 3B illustrate an example result after the overburden of the reversal material 302 is removed.
• the first relief pattern 202 can be removed from the substrate segment 100. As shown in FIG. 4A and 4B, the raised features 204 that are formed of the first layer 106 in the first relief pattern 202 are removed, and the reversal material 302 still remains.
• a wet etch back process can be applied.
• the wet etch back process can apply a solvent system in which the reversal material 302 is weakly soluble relative to the first relief pattern 202.
• An exemplary solvent system can include either a dilute aqueous developer or a solution composed of casting solvent.
• the reversal material 302 When the first relief pattern 202 is removed, the reversal material 302 accordingly forms a second relief pattern 402 that is essentially an inverse of the first relief pattern 202. As shown in FIGS. 4A and 4B, the second relief pattern 402 can have a raised feature 406 that is formed of the reversal material 302, and openings 404 that uncover the underlying layer 104.
• a fill material 502 can then be deposited on the substrate segment 100 (and on the second relief pattern 402) to fill the openings 404 defined by the second relief pattern 402.
• the fill material 502 can be selected as, or comprised of, a material that is sensitive to the photo-acid that can be generated within the reversal material 302.
• the fill material 502 can be an acid-sensitive overcoat.
• the fill material 502 when is in contact with the photo acid that generated by the photo-acid generator in the reversal material 302, becomes soluble to a particular developer. Any overburden of the fill material 502 can be subsequently removed using planarization techniques, which are described above to remove the overburden of the reversal material 302.
• FIGS. 5A and 5B show an exemplary embodiment of the deposition of the fill material 502.
• the fill material 502 can be a co- or ter-polymer similar in design to the reversal material 302 in that the primary design requirements are casting solvent solubility, developer solubility and etch resistance to maximize the contrast between the fill material 502 and the reversal material 302.
• a list of common monomers include styryl groups, low molecular weight acrylates and lactones similar to the reversal material 302, however the ratio of the monomers can vary significantly.
• FIGS. 6 A and 6B show an exposure of the second relief pattern to a pattern of a second actinic radiation 506.
• the pattern of the second actinic radiation 506 can expose selected portions (or all of) of the raised feature (e.g., 406) in the second relief pattern 402 based on a mask 504.
• a selected portion 508 of the raised feature 406 in the second relief pattern 402 can be exposed by the second actinic radiation 506, where the raised feature 406 is formed of the reversal material 302.
• an acid can be generated by the photo-acid generator according to the second actinic radiation 506 within the selected portions (e.g., 508) of the raised feature 406 in the second relief pattern 402.
• the photo-acid can be diffused into surrounding materials, which can be the fill material 502, for example.
• the acid diffusion from the second relief pattern 402 to the fill material 502 can be precisely controlled. For example, a length or a distance of the acid diffusion can be controlled by a type of the acid, and/or by a time and a temperature of a thermally activated diffusion process (e.g., a diffusion bake) that drive the photo-acid to diffuse from the second relief pattern 402 to the fill material 502.
• a thermally activated diffusion process e.g., a diffusion bake
• the selected portion 508 can be a rectangular section of the raised feature 406 in the second relief pattern 402.
• the acid can be generated by the photo-acid generator in such a rectangular section.
• the acid can further diffuse into the fill material 502 through interfaces 510 between the selected portion 508 of the second relief pattern 402 and the fill material 502 by applying the thermally activated diffusion process.
• the acid can be disposed in slot-shaped regions 502’ of the fill material 502.
• the photo-acid can cause the slot-shaped regions 502’ of the fill material 502 to be soluble to a developer.
• FIG. 6B illustrate the narrow and slot-shaped regions 502’ that are formed in the fill material 502, and formed by driving the photo-acid generated in the selected portions (e.g., 508) of the second relief pattern 402 into the fill material 502.
• the substrate segment 100 can then be developed with a particular developer to remove the slot-shaped regions 502’ of the fill material 502.
• Example developers can include an aqueous solution of 0.26N tetramethyl ammonium hydroxide (TMAH), dilutions of aqueous TMAH such as 0.13N or aqueous TMAH with the addition of various surfactants.
• the particular developer can dissolve the slot-shaped regions 502’ of the fill material 502, and slot-shaped openings 602 can subsequently be formed in the fill material 502 adjacent to the reversal material 302.
• portions of the underlying layer 104 can be uncovered by the slot-shaped openings 602.
• the slot-shaped openings 602 can have a critical dimension (or width) defined by an acid diffusion length of the photo-acid that diffuses from the selected portions (e.g., 508) of the second relief pattern into the fill material 502.
• the acid diffusion length can be controlled to single-digit nanometer dimensions. It should be noted that the particular developer impacts the reversal material 302 very less. Thus, the reversal material 302 is unaffected when the substrate segment 100 is developed with the particular developer.
• a third relief pattern 802 can subsequently be formed to include the slot shaped openings 602 and raised features that are formed of the reversal material 302 and the fill material 502.
• the third relief pattern 802 can be transferred into the underlying layer 104 through an etching process to form openings 702.
• the openings 702 can be slot-shaped openings 702. The slot-shaped openings 702 can extend through the fill material 502 and the underlying layer 104 so that the substrate 102 can be uncovered.
• the etching process can be a wet etching or a dry etching (e.g., an anisotropic plasma etching).
• the fill material 502, the slot-shaped openings 602 positioned in the fill material 502, and the reversal material 302 can function as a combined etch mask for transferring the slot-shaped pattern defined by the slot-shaped openings 602 into the underlying layer 104.
• FIGS. 7A and 7B are merely an exemplary embodiment of the third relief pattern 802.
• the third relief pattern 802 can include hole-shaped openings, line shaped openings, or openings with other shapes.
• the third relief pattern 802 can be transferred into the underlying layer 104 to form holes, trenches, or openings with corresponding shapes accordingly in FIG. 8 A and 8B.
• the reversal material 302 and the fill material 502 can be removed by a plasma process, such as an 02 ashing process.
• a plasma process such as an 02 ashing process.
• a portion of the opening 702 in the fill material 502 can be removed, and a portion of the opening 702 in the underlying layer 104 can still remain.
• the portion of the opening 702 that remains in the underlying layer 104 can become openings 902.
• the openings 902 can have a slot shape, a hole shape, a trench shape, or other shapes according to the third relief pattern 802.
• the openings 902 can further be filled with conductive materials to form narrow slot contacts that can connect active regions (e.g., a source region, a drain region, or a doped region) in the substrate 102 and other components (e.g., a transistor, a metal line, or a capacitor) above the substrate 102.
• active regions e.g., a source region, a drain region, or a doped region
• other components e.g., a transistor, a metal line, or a capacitor
• the methods mentioned above illustrate an anti-spacer patterning process for making narrow slot contacts without a solubility neutralizing treatment.
• the anti-spacer patterning process in the present disclosure provides a “freeze-less” anti-spacer patterning method that enables accessing narrow slot contacts defined by diffusion lengths by inverting a pattern and using compositions resistive to solubility shifts.
• the anti-spacer patterning process herein enables access to pattern resolutions well below the theoretical limit of 365 and 248 nm lithography used in 200 mm sites.
• CDs defined by an acid diffusion from the reversal material allow for precise control to achieve pattern resolutions on the order of 40 - 100 nm. Aspect ratios below 10:1 can especially benefit to improve etch performance and mitigate pattern collapse.
• Novolak photoresists are a mature technology capable of achieving high sidewall angles that help maximize aspect ratios to form sub-resolution trenches.
• substrate or “target substrate” as used herein generically refers to an object being processed in accordance with the invention.
• the substrate may include any material portion or structure of a device, particularly a semiconductor or other electronics device, and may, for example, be a base substrate structure, such as a semiconductor wafer, reticle, or a layer on or overlying a base substrate structure such as a thin film.
• substrate is not limited to any particular base structure, underlying layer or overlying layer, patterned or un-patterned, but rather, is contemplated to include any such layer or base structure, and any combination of layers and/or base structures.
• the description may reference particular types of substrates, but this is for illustrative purposes only.

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