Post-treatment after development of metal-containing photoresist

Abstract

The various embodiments described herein relate to methods, apparatuses, and systems for post-development processing of metal-containing photoresist masks to improve lithography performance. After development, the metal-containing photoresist mask may be exposed to one or more of the following processes: thermal annealing, plasma exposure, exposure to a reactive gas, and selective deposition of a protective film. In some embodiments, the metal-containing photoresist mask is exposed to one or more reactive gases to change the composition of the photoresist mask and / or selectively deposit a protective film on the top surface and sidewalls of the photoresist mask. The processed photoresist mask may exhibit an increase in line CD for reduction of dose-to-size and improvement of etch resistance.

Description

Technical Field

[0001] Incorporation by reference: As part of this application, a PCT application form is filed simultaneously with this specification. Each application specified in this simultaneously filed PCT application form and for which this application claims benefit or priority is hereby incorporated by reference in its entirety for all purposes into this specification.

[0002] Embodiments of this specification relate to the processing of photoresist materials, and more particularly, to the processing of metal-containing photoresist materials after development in semiconductor fabrication.

[0003] The fabrication of semiconductor devices such as integrated circuits is a multi-step process involving photolithography. Generally, this process includes depositing materials onto a wafer and patterning the materials using lithographic techniques to form the structural features (e.g., transistors and circuits) of the semiconductor device. Typical steps in a photolithography process known in the art include preparing a substrate, applying a photoresist by spin coating or the like, exposing the photoresist to light in a desired pattern to render the exposed areas of the photoresist somewhat soluble in a developer, developing by applying the developer to remove either the exposed or unexposed areas of the photoresist, and performing subsequent processing to form features on the areas of the substrate from which the photoresist has been removed, such as by etching or material deposition.

[0004] The evolution of semiconductor design has been driven by the need to form ever-smaller features on semiconductor substrate materials. This technological progress is characterized in "Moore's Law" by the doubling of transistor density in high-density integrated circuits every two years. In fact, chip design and manufacturing have advanced to the point where the latest microprocessors can contain billions of transistors and other circuit features on a single chip. Individual features on such chips can be on the order of 22 nanometers (nm) or less, and in some cases less than 10 nm.

[0005] One challenge in manufacturing devices with such small features is the ability to reliably and reproducibly form photolithography masks with sufficient resolution. Current photolithography processes typically use 193 nm ultraviolet (UV) light to expose photoresist. The fact that the light has a wavelength significantly longer than the desired size of the features created on the semiconductor substrate causes inherent problems. To achieve feature sizes smaller than the wavelength of the light, the use of complex resolution enhancement techniques such as multipatterning is required. Therefore, there has been a great deal of interest and research effort in the development of photolithography techniques that use short-wavelength light, such as extreme ultraviolet (EUV) light with a wavelength of 10 nm to 15 nm, for example 13.5 nm.

[0006] However, EUV photolithography processes can present challenges such as reduced output and light loss during patterning. Conventional organic chemically amplified resists (CARs), similar to those used in 193 nm UV lithography, have potential drawbacks when used in EUV lithography, particularly due to their low absorption coefficients in the EUV region and the potential for blurring or line edge roughness due to the diffusion of photoactivated species. Additionally, small features patterned with conventional CAR materials can result in high aspect ratios that pose a risk of pattern collapse in order to provide the etching resistance necessary to pattern the underlying device layer. Accordingly, there remains a need for improved EUV photoresist materials having properties such as reduced thickness, greater absorbance, and greater etching resistance.

[0007] The background art provided herein is intended to generally present the content of the present disclosure. Within the scope described in this background art, research by the inventors named at the present time, as well as aspects of the description that cannot be separately considered as prior art at the time of filing, are not admitted as prior art against the present disclosure, whether explicitly or implicitly.

Summary of the Invention

[0008] Disclosed herein is a method of processing a substrate within a process chamber. The method includes providing a substrate within the process chamber, the substrate being a semiconductor substrate comprising a substrate layer and a developed metal-containing photoresist mask over the substrate layer, and processing the developed metal-containing photoresist mask by exposing it to one or more reactive gases.

[0009] In some embodiments, the method further includes etching the substrate layer after processing the developed metal-containing photoresist mask and forming a concave feature using the developed metal-containing photoresist mask, and the critical dimension of the developed metal-containing photoresist mask is maintained during etching. In some embodiments, processing the developed metal-containing photoresist mask includes selectively depositing a protective layer on the developed metal-containing photoresist mask compared to the substrate layer, and the protective layer includes carbon or carbide, nitride, sulfide, fluoride, oxide, or elemental metal. In some embodiments, selectively depositing the protective layer includes exposing the developed metal-containing photoresist mask to a metal precursor. In some embodiments, the metal precursor includes a metal halide or an organometallic precursor. In some embodiments, the metal precursor is generated in-situ within the process chamber. In some embodiments, the one or more reactive gases include a carbon-containing precursor or a metal halide. In some embodiments, the carbon-containing precursor includes metal carbonyl, carbon dioxide, or carbon monoxide. In some embodiments, processing the developed metal-containing photoresist mask includes exposing the developed metal-containing photoresist mask to a carbon-containing precursor and selectively depositing a metal-containing layer on the developed metal-containing photoresist mask. In some embodiments, processing the developed metal-containing photoresist mask increases one or more of the following material properties: the density, etch resistance, and critical dimension of the developed metal-containing photoresist mask. In some embodiments, processing the developed metal-containing photoresist mask includes thermally annealing the developed metal-containing photoresist mask at a high temperature of about 100°C to about 250°C. In some embodiments, processing the developed metal-containing photoresist mask includes exposing the developed metal-containing photoresist mask to one or more reactive gases in a plasma. In some embodiments, the developed metal-containing photoresist mask includes a metal oxide-containing extreme ultraviolet (EUV) photoresist mask. In some embodiments, the metal oxide-containing EUV photoresist mask includes tin oxide.In some embodiments, the method further includes developing a metal-containing photoresist to selectively remove a portion of the metal-containing photoresist to form a developed metal-containing photoresist mask, and developing the metal-containing photoresist includes exposing the metal-containing photoresist to a wet development chemical or a dry development chemical.

[0010] Also provided herein is a method of processing a substrate within a process chamber. The method includes providing a substrate within the process chamber, wherein the substrate is a semiconductor substrate comprising a substrate layer and a developed metal-containing photoresist mask on the substrate layer, and performing one or more of the following operations: (i) thermally annealing the developed metal-containing photoresist mask; (ii) exposing the developed metal-containing photoresist mask to a plasma; (iii) exposing the developed metal-containing photoresist mask to one or more reactive gases; and (iv) selectively depositing a protective layer on the developed metal-containing photoresist mask as compared to the substrate layer to process the developed metal-containing photoresist mask.

[0011] In some embodiments, thermally annealing the developed metal-containing photoresist mask includes exposing the developed metal-containing photoresist mask to a high temperature of about 100°C to about 250°C to reduce the defect rate and line width roughness (LWR) in the developed metal-containing photoresist mask. In some embodiments, exposing the developed metal-containing photoresist mask to plasma densifies the developed metal-containing photoresist mask to reduce LWR. In some embodiments, exposing the developed metal-containing photoresist mask to one or more reactive gases includes exposing the developed metal-containing photoresist mask to carbon monoxide, carbon dioxide, metal carbonyl, organometallic, metal halide, or combinations thereof to increase the etch resistance and / or critical dimension of the developed metal-containing photoresist mask. In some embodiments, selectively depositing a protective layer on the developed metal-containing photoresist mask includes selectively depositing carbon or carbide, nitride, sulfide, fluoride, oxide, or elemental film to increase the critical dimension of the developed metal-containing photoresist mask. In some embodiments, the method further includes developing the metal-containing photoresist to selectively remove a portion of the metal-containing photoresist to form a developed metal-containing photoresist mask, etching a substrate layer, and using the developed metal-containing photoresist mask to form a concave feature, and the processing of the developed metal-containing photoresist mask is performed between development and etching. In some embodiments, the developed metal-containing photoresist mask includes a metal oxide-containing EUV photoresist mask.

[0012] Also, in this specification, an apparatus for processing a substrate within a process chamber is provided. The apparatus includes a substrate support within the process chamber, the substrate support being configured to support a substrate including a substrate layer and a developed metal-containing photoresist mask on the substrate layer, and a reactive gas source in fluid communication with the process chamber and configured to feed one or more reactive gases toward the substrate support via one or more gas inlets to process the developed metal-containing photoresist mask.

[0013] In some embodiments, the apparatus further includes one or more heating elements configured to heat the substrate to a high temperature during processing of the developed metal-containing photoresist mask. In some embodiments, the one or more heating elements comprise one or more LEDs within the substrate support. In some embodiments, the apparatus further includes a plasma source configured to generate plasma during processing of the developed metal-containing photoresist mask. In some embodiments, the reactive gas source configured to feed one or more reactive gases is configured to selectively deposit a protective film on the developed metal-containing photoresist mask during processing of the developed metal-containing photoresist mask. In some embodiments, the process chamber configured to process the developed metal-containing photoresist mask is configured to perform development of the metal-containing photoresist mask. In some embodiments, the process chamber configured to process the developed metal-containing photoresist mask is configured to perform pattern transfer etching of the substrate layer of the substrate using the developed metal-containing photoresist mask. In some embodiments, the one or more reactive gas species include organic gas species, organometallic gas species, metal-containing gas species, or combinations thereof. In some embodiments, the one or more reactive gas species include oxygen-containing gases, carbon-containing gases, hydrogen-containing gases, nitrogen-containing gases, halogen-containing gases, or combinations thereof.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0027] The present disclosure generally relates to the field of semiconductor processing. In particular, the present disclosure is directed to post-development processing of photoresists including metal-containing photoresists. Such metal and / or metal oxide-containing photoresists may be subjected to processes that change the chemical, physical, and / or optical properties of the photoresist after development and before pattern transfer. The photoresist processing improves the performance of the photoresist. For example, the photoresist processing can reduce the dose-to-size (DtS), reduce the LWR, increase the line CD, improve the etch resistance, reduce the gas evolution of tin or other elements, and / or reduce the defects / line breaks.

[0028] Reference will now be made in detail to specific embodiments of the present disclosure. Examples of specific embodiments are shown in the accompanying drawings. While the present disclosure will be described in conjunction with these specific embodiments, it will be understood that the present disclosure is not intended to be limited to such specific embodiments. On the contrary, it is intended to cover alternatives, modifications, and equivalents that may be included within the spirit and scope of the present disclosure. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. The present disclosure may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail so as not to unnecessarily obscure the present disclosure.

[0029] Patterning of thin films in semiconductor processing is often an important step in semiconductor fabrication. Patterning involves lithography. In conventional photolithography such as 193 nm photolithography, a pattern is printed on a photosensitive photoresist film by exposing the photoresist to photons within a selected area defined by a photomask, thereby causing a chemical reaction in the exposed photoresist, resulting in a chemical contrast that can be utilized to remove specific portions of the photoresist in a development step to form a pattern. The patterned and developed photoresist film can then be used as an etching mask to transfer the pattern to an underlying film composed of metal, oxide, etc.

[0030] (As defined by the International Technology Roadmap for Semiconductors) Advanced technology nodes include 22 nm, 16 nm, and subsequent nodes. For example, at the 16 nm node, the width of vias or lines in a damascene structure is typically about 30 nm or less. Scaling of features on advanced semiconductor integrated circuits (ICs) and other devices is driving lithography to improve resolution.

[0031] Extreme ultraviolet (EUV) lithography can extend lithography technology by moving to a shorter imaging source wavelength than can be achieved with conventional photolithography methods. EUV light sources with wavelengths of about 10 - 20 nm, or 11 - 14 nm, such as a wavelength of 13.5 nm, can be used in state-of-the-art lithography tools, also called scanners. Since EUV radiation is strongly absorbed by a wide range of solid and fluid materials including quartz and water vapor, it operates in a vacuum.

[0032] EUV lithography utilizes an EUV resist patterned to form a mask for use in etching the underlying layer. The EUV resist may be a polymer-based chemically amplified resist (CAR) obtained by a liquid-based spin-on technique. Alternatives to CAR are available from Inpria Corp. (Corvallis, Oregon), and are, for example, metal oxide-containing films that are directly photopatternable, such as those described in U.S. Patent Application Publication No. 2017 / 0102612, U.S. Patent Application Publication No. 2016 / 0216606, and U.S. Patent Application Publication No. 2016 / 0116839, the disclosures of which are incorporated herein by reference at least with respect to the disclosure of the at least photopatternable metal oxide-containing film. Such films may be provided by a spin-on technique or by dry vapor deposition. The metal oxide-containing film can be directly (i.e., without using a separate photoresist) patterned by EUV exposure in a vacuum atmosphere that provides a patterning resolution of less than 30 nm, as described in, for example, U.S. Patent No. 9,996,004, issued June 12, 2018, entitled "EUV PHOTOPATTERNING OF VAPOR-DEPOSITED METAL OXIDE-CONTAINING HARDMASKS", and / or International Publication No. WO2019 / 217749, published May 9, 2019, and entitled "METHODS FOR MAKING EUV PATTERNABLE HARD MASKS", International Application No. PCT / US19 / 31618. The disclosures of the above related to at least the composition, deposition, and patterning of the directly photopatternable metal oxide film for forming an EUV resist mask are incorporated herein by reference. Generally, patterning involves exposing the EUV resist with EUV radiation to form a photopattern in the resist, followed by developing to remove a portion of the resist according to the photopattern to form the mask.

[0033] Directly photo-patternable EUV or DUV resists can be composed of, or contain, metals and / or metal oxides mixed within an organic component. The metal / metal oxides can enhance the absorption of EUV or DUV photons, generate secondary electrons, and / or exhibit high etch selectivity with respect to underlying film stacks and device layers. These resists are developed using wet (solvent) techniques, which require the wafer to be transferred to a track where the wafer is exposed to a developing solvent, dried, and baked. Such resists can also be developed using dry techniques, or a combination of wet and dry techniques, as described herein.

[0034] Generally, a resist can be used as a positive resist or a negative resist by controlling the chemical properties of the resist and / or the solubility or reactivity of the developer. It would be beneficial to have an EUV or DUV resist that can serve as either a negative resist or a positive resist.

[0035] Techniques related to the EUV process may be described below, but such techniques may also be applicable to other next-generation lithography techniques. Various radiation sources can be used, including EUV (generally about 13.5 nm), DUV (deep UV, generally in the range of 248 nm or 193 nm with an excimer laser source), X-rays (including EUV in the lower energy range of the X-ray spectrum), and e-beam (including a wide range of energies).

[0036] Such methods include contacting a substrate having exposed hydroxyl groups with a hydrocarbyl-substituted Suzuki capping agent to form a hydrocarbyl-terminated SnO film as an imaging / photoresist layer on the surface of the substrate. Specific methods may depend on the specific materials and applications used in semiconductor substrates and final semiconductor devices. Thus, the methods described in this application are merely examples of methods and materials that can be used in this technology. x The methods described herein are merely examples of methods and materials that can be used in this technology.

[0037] This disclosure relates to post-development processing of photoresists. A metal- or metal-oxide-containing photoresist may be deposited wet or dry. The metal- or metal-oxide-containing photoresist has high absorption of EUV radiation, whereby the photoresist can be patterned by EUV exposure to form exposed and unexposed regions. After the exposed or unexposed regions of the metal- or metal-oxide-containing photoresist that have been photopatterned by development are selectively removed, it is possible to process the developed photoresist. Such processing may include one or more of the following operations: (i) thermal annealing, (ii) plasma exposure, (iii) reactive gas exposure, and (iv) selective deposition of a protective layer. Such processing can achieve one or more of the following advantages: reduction of defect rate, reduction of LWR, reduction of DtS, reduction of gas emission (e.g., gas emission of tin), increase of etching resistance, and increase of line CD, thereby improving the performance of the metal- or metal-oxide-containing photoresist during etching.

[0038] FIG. 1 shows a flowchart of an exemplary method for depositing, developing, and processing a photoresist according to some embodiments. The operations of process 100 may be performed in a different order and / or with a different, fewer, or additional number of operations. One or more of the operations of process 100 can be performed using the apparatus described in any one of FIGS. 10-13. In some embodiments, the operations of process 100 may be implemented at least in part in accordance with software stored on one or more non-transitory computer-readable media.

[0039] In block 102 of process 100, a layer of photoresist is deposited. This can be either a dry deposition process such as a vapor deposition process or a wet deposition process such as a spin-on deposition process. In one embodiment, the metal-containing precursor is deposited as a solution by using a liquid-based spin-on technique. In another embodiment, the metal-containing precursor is deposited in the form of a vapor by using a dry technique (e.g., chemical vapor deposition).

[0040] In block 104 of process 100, the backside or bevel of the substrate can be optionally cleaned and / or the edge beads of the photoresist deposited in the previous step can be removed. Such cleaning or removal steps can be useful for removing particles that may be present after the photoresist layer is deposited. The removal step can include processing the wafer in a wet metal oxide (MeOx) edge bead removal (EBR) step.

[0041] In block 106 of process 100, a post-application bake (PAB) or post-application treatment can be optionally performed. Such treatment can improve the etching resistance of the unexposed material to aqueous or non-aqueous solutions. In one example, such treatment can enhance the chemical composition difference (or contrast) between the unexposed and exposed regions, and thus the PAB operation is performed. In another example, such treatment may reduce the chemical composition difference (or contrast) between the unexposed and exposed regions, and thus the PAB operation is not performed. In yet another example, the use of PAB removes residual moisture from the layer and forms a cured resist film. PAB involves a heat treatment, chemical exposure, and / or some combination of moisture that increases the EUV sensitivity of the film, thereby reducing the EUV dose required to develop a pattern in the film. In certain embodiments, the PAB step is performed at a temperature above about 100 °C, or about 100 °C to about 200 °C, or about 100 °C to about 250 °C. In other embodiments, the PAB step is performed at a temperature of about 190 °C to about 350 °C in the absence of an O-containing gas. In another example, the post-application treatment includes exposing the film to an inert gas or CO 2 and this can optionally include cooling or heating. The use of an inert gas can provide metal-oxygen-metal species, and the use of CO 2 can provide metal carbonate species in the film.

[0042] In block 108 of process 100, the film is exposed to EUV radiation and the pattern is developed. Generally, EUV exposure causes a change in the chemical composition of the film, resulting in a contrast in the etching selectivity that can be used to remove a portion of the film. Such a contrast can provide a positive resist. However, it will be understood that EUV exposure can instead create a contrast such that the unexposed regions are selectively removed. Such a contrast can provide a negative resist as described herein. EUV exposure can include, for example, exposure having a wavelength in the range of about 10 nm to about 20 nm (e.g., about 13.5 nm) in a vacuum atmosphere.

[0043] In block 110 of process 100, an optional post-exposure bake (PEB) is performed on the exposed film, thereby further removing residual moisture, promoting chemical condensation within the film, or increasing the contrast in the etching selectivity of the exposed film, or post-treating the film in any useful manner. In one example, such a treatment may reduce the difference in chemical composition (or contrast) between the unexposed and exposed regions, and thus the PEB operation is not performed. In another example, when the exposed film is heat-treated (e.g., at a low temperature and / or optionally in the presence of various chemical species) and exposed to a stripping agent or a positive developer (e.g., an aqueous solution of a halide-based acid such as HCl, HBr, HI, or a combination thereof), the reactivity within the EUV-exposed or EUV-unexposed portion of the resist can be promoted. In another example, the exposed film is heat-treated (e.g., at a low temperature) to further crosslink the ligands within the EUV-unexposed portion of the resist, thereby providing an EUV-exposed portion that can be selectively removed upon exposure to a stripping agent (e.g., a positive developer). In yet another example, the PEB is omitted.

[0044] In block 112 of process 100, the photoresist pattern is developed by positive or negative development. In various embodiments of development, the unexposed regions are selectively removed (to provide a pattern within a negative resist). These steps can be a wet process using one or more developers or development solutions, followed by an optional rinse operation (e.g., using deionized water or another solvent) or an optional drying operation (e.g., using air or under inert conditions with optional heat). In certain embodiments, the development step is a wet process applied to a tin-based film. In other embodiments, the development step is a dry process applied to a tin-based film. For example, the dry process includes a halide-containing chemical.

[0045] In block 114 of process 100, the photoresist is processed before pattern transfer. The processing may be a heat treatment, a plasma treatment, a chemical treatment, a selective deposition treatment, or a combination of the aforementioned treatments. The heat treatment can expose the photoresist to a high temperature of about 200 °C to about 300 °C to reduce the defect rate and LWR. The plasma treatment can expose the photoresist to a plasma such as an in-situ plasma or a remote plasma to densify the photoresist and reduce the LWR. The chemical treatment can expose the photoresist to reactive chemical species such as a halide-based species (e.g., tungsten hexafluoride) or a carbon-containing precursor (e.g., carbon monoxide, metal-organic precursor) to improve the etching resistance, reduce the gas evolution, and increase the line CD. The selective deposition treatment can expose the photoresist to a chemical precursor to selectively deposit a protective coating on the photoresist to reduce the DtS, improve the etching resistance, reduce the gas evolution, and increase the line CD. To improve the performance of the photoresist during pattern transfer, any one or more of the aforementioned treatments are applied to the photoresist after development.

[0046] In block 116 of process 100, one or more substrate layers are etched using a photoresist mask for pattern transfer. Such substrate layers are under the photoresist mask and may be removable by lithographic etching. Pattern transfer etching can etch the material to a desired depth and form a plurality of patterned features. In some embodiments, the one or more substrate layers are amorphous carbon (a-C), amorphous silicon (a-Si), tin oxide (e.g., SnO x ), silicon oxide (e.g., SiO 2 ), silicon oxynitride (e.g., SiO x N y ), silicon oxycarbide (e.g., SiO x C y ), silicon nitride (e.g., Si 3 N 4 ), titanium oxide (e.g., TiO 2 ), titanium nitride (e.g., TiN), tungsten (e.g., W), doped carbon (e.g., W-doped C), tungsten oxide (e.g., WO x ), hafnium oxide (e.g., HfO 2 ), zirconium oxide (e.g., ZrO 2 ), and aluminum oxide (e.g., Al 2 O 3 ) may be included. Defects or variations in the CD of the photoresist mask are replicated in the material being patterned during pattern transfer etching. In addition, if the etching resistance is low, it will adversely affect the transfer of the pattern to the underlying substrate layer during the etching process. Post-development processing of the photoresist mask reduces ongoing problems and ensures the success of pattern transfer during pattern transfer etching.

[0047] Figure 2 shows a flowchart of an exemplary method for processing a photoresist on a substrate after development, according to some embodiments. The operations of process 200 may be performed in a different order and / or with a different, fewer, or additional number of operations. Aspects of process 200 may be described with reference to FIGS. 3A-3D, FIGS. 4A-4D, FIGS. 5A-5D, and FIGS. 6-9. One or more operations of process 200 may be performed using the apparatus described in any one of FIGS. 10-13. In some embodiments, the operations of process 200 may be implemented, at least in part, in accordance with software stored on one or more non-transitory computer-readable media.

[0048] In block 210 of process 200, a metal-containing photoresist is developed to selectively remove a portion of the metal-containing photoresist and form a developed metal-containing photoresist mask. In some embodiments, the metal-containing photoresist may be a metal-containing EUV photoresist. In some embodiments, the metal-containing EUV photoresist includes tin oxide.

[0049] The metal-containing photoresist is provided on a substrate. Prior to development, a metal-containing photoresist film is deposited on the substrate using a wet or dry deposition process. The metal-containing photoresist film is exposed to radiation, such as EUV radiation, according to a desired pattern to form exposed and unexposed regions of the metal-containing photoresist film. Generally speaking, exposure to radiation causes a change in the chemical composition of the film, resulting in a contrast in the etching selectivity that can be used to remove a portion of the film. The metal-containing photoresist film is then developed by positive or negative development using a wet or dry developer chemical. Details of the deposition, exposure, development, and other processes of the photoresist film are described below.

[0050] Deposition of Metal-Containing Resist Material The photoresist film can be deposited on a substrate. Such a film can be deposited by using a wet or dry deposition process, in which a metal-containing precursor (e.g., a tin-containing precursor as described herein) is provided in the vicinity of the substrate. In one embodiment, the metal-containing precursor is deposited as a solution by using a liquid-based spin-on technique. In another embodiment, the metal-containing precursor is deposited in the form of vapor by using a dry technique (e.g., chemical vapor deposition). In the present disclosure, the metal-containing precursor is often a tin-containing precursor, but other metal atoms can also be used.

[0051] The layers and films described herein may contain elements (e.g., metal atoms or non-metal atoms) having a high photoabsorption cross-section, such as 1×10 7 cm 2 / mol or more. Such elements can be supplied by depositing one or more precursors to provide an imaging layer.

[0052] In some embodiments, the film is a radiation-sensitive film (e.g., an EUV-sensitive film). This film can then serve as an EUV resist, as further described herein. In certain embodiments, the layer or film can contain one or more ligands (e.g., EUV-labile ligands) that can be removed, cleaved, or cross-linked by radiation (e.g., EUV or DUV radiation).

[0053] The precursor can provide a patterning-capable film sensitive to radiation (or a patterning radiation-sensitive film or a photopatternable film). Such radiation can include EUV radiation, DUV radiation, or UV radiation provided by irradiating through a patterned mask, thereby becoming patterned radiation. The film itself can be modified by being exposed to such radiation so as to be radiation-sensitive or photosensitive. In certain embodiments, the precursor is an organometallic compound containing at least one metal center.

[0054] The precursor can have any useful number and type of ligands. In some embodiments, the ligand can be characterized by its ability to react in the presence of a counter-reagent or in the presence of patterned radiation. For example, the precursor can include a ligand that reacts with a counter-reagent that can introduce a linkage (e.g., an -O-linkage) between metal centers. In another example, the precursor can include a ligand that desorbs in the presence of patterned radiation. Such EUV-labile ligands can include a branched or straight-chain alkyl group having a beta hydrogen, as well as any of those described herein for R of formula (I) or (II). In one embodiment, the precursor is a capping agent having 2, 3, or more hydrophobic ligands (e.g., an organic ligand including alkyl, alkenyl, or alkynyl optionally substituted with C 2-6 alkyl, alkenyl, or alkynyl optionally substituted with C

[0055] Other EUV-labile ligands include an alkyl group, an alkenyl group, or an alkynyl group, which can be branched or straight-chain. Still other EUV-labile ligands include an aryl group such as an aryl group having one, two, or three rings. Such alkyl, alkenyl, alkynyl, and aryl groups can be substituted with one or more halo (e.g., one or more fluoro). Non-limiting labile ligands include optionally substituted C 1-12 alkyl, optionally substituted C 2-12 alkenyl, optionally substituted C 2-12 alkynyl, optionally substituted C 1-12 haloalkyl, optionally substituted C 2-12 haloalkenyl, optionally substituted C 2-12 haloalkynyl, optionally substituted aryl, or optionally substituted haloaryl.

[0056] The precursor can be any useful metal-containing precursor such as an organometallic agent, a metal halide, or a capping agent (e.g., as described herein). In non-limiting examples, the precursor has the formula (I): M a R b (I) comprising a structure having wherein M is a metal or atom having a high EUV absorption cross-section, and each R is independently H, halo, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted cycloalkenyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted alkoxy, optionally substituted alkanoyloxy, optionally substituted aryl, optionally substituted amino, optionally substituted bis(trialkylsilyl)amino, optionally substituted trialkylsilyl, oxo, an anionic ligand, a neutral ligand, or a polydentate ligand, a ≧ 1, and b ≧ 1.

[0057] In another non-limiting example, the precursor has the formula (II): M a R b L c (II) comprising a structure having wherein M is a metal or atom having a high EUV absorption cross-section, each R is independently halo, optionally substituted alkyl, optionally substituted aryl, optionally substituted amino, optionally substituted alkoxy, or L, each L is independently a ligand that reacts with a counteragent, an anionic ligand, a neutral ligand, a polydentate ligand, an ion, or another moiety, and R and L together with M can optionally form a heterocyclyl group, or R and L together can optionally form a heterocyclyl group, a ≧ 1, b ≧ 1, and c ≧ 1.

[0058] In some embodiments, each ligand in the precursor can be a ligand that reacts with a reverse reactant. In one example, the precursor includes a structure having formula (II), and each R is independently L. In another example, the precursor has the formula (IIa): M a L c (IIa) and includes a structure having where M is a metal or atom having a high EUV absorption cross-section, each L is independently a ligand, ion, or other moiety that reacts with a reverse reactant, two Ls can together optionally form a heterocyclyl group, a ≧ 1, and c ≧ 1. In certain embodiments of formula (IIa), a is 1. In further embodiments, c is 2, 3, or 4.

[0059] For any of the formulas herein, M can be a metal, metalloid, or atom having a high patterning radiation absorption cross-section (e.g., an EUV absorption cross-section of 1×10 7 cm 2 / mol or greater). In some embodiments, M is tin (Sn), bismuth (Bi), tellurium (Te), cesium (Cs), antimony (Sb), indium (In), molybdenum (Mo), hafnium (Hf), iodine (I), zirconium (Zr), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), silver (Ag), platinum (Pt), and lead (Pb). In further embodiments, in formula (I), (II), or (IIa), M is Sn, a is 1, and c is 4. In other embodiments, in formula (I), (II), or (IIa), M is Sn, a is 1, and c is 2. In certain embodiments, M is Sn(II) (e.g., in formula (I), (II), or (IIa)), thereby providing a precursor that is a Sn(II)-based compound. In other embodiments, M is Sn(IV) (e.g., in formula (I), (II), or (IIa)), thereby providing a metal precursor that is a Sn(IV)-based compound. In certain embodiments, the precursor includes iodine (e.g., as in periodate).

[0060] For any formula in this specification, each R is independently H, halo, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted cycloalkenyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted alkoxy (e.g., -OR 1 , where R 1 can be optionally substituted alkyl), optionally substituted alkanoyloxy, optionally substituted aryl, optionally substituted amino, optionally substituted bis(trialkylsilyl)amino, optionally substituted trialkylsilyl, oxo, anionic ligand (e.g., oxide, chloride, hydride, acetate, iminodiacetate, propanoate, butanoate, benzoate, etc.), neutral ligand, or polydentate ligand.

[0061] In some embodiments, the optionally substituted amino is -NR 1 R 2 , where each R 1 and R 2 is independently H or alkyl, or R 1 and R 2 together with the nitrogen atom to which each is attached form a heterocyclyl group as defined herein. In other embodiments, the optionally substituted bis(trialkylsilyl)amino is -N(SiR 1 R 2 R 3 ), where each R 2 , R 1 , and R 2 is independently optionally substituted alkyl. In still other embodiments, the optionally substituted trialkylsilyl is -SiR 3 R 1 R 2 R 3 , where each R 1 , R 2 , and R 3 is independently optionally substituted alkyl.

[0062] In other embodiments, the formula is -NR 1 R 2 a first R (or first L) that is 1 R 2 and a second R (or second L) that is 1 and R 2 each independently is H or optionally substituted alkyl, or R 1 from the first R (or first L) and R 1 from the second R (or second L) together with the nitrogen atom and metal atom to which each is attached form a heterocyclyl group as defined herein. In yet other embodiments, the formula is -OR 1 a first R that is 1 and a second R that is 1 each independently is H or optionally substituted alkyl, or R 1 from the first R and R 1 from the second R together with the oxygen atom and metal atom to which each is attached form a heterocyclyl group as defined herein.

[0063] In some embodiments, at least one of R or L (e.g., in formula (I), (II), or (IIa)) is optionally substituted alkyl. Non-limiting alkyl groups include, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, or t-butyl, etc., C n H 2n+1 where n is 1, 2, 3, or more. In various embodiments, R or L has at least one beta hydrogen, beta halogen, or beta fluorine. In other embodiments, at least one of R or L is halo-substituted alkyl (e.g., fluoro-substituted alkyl).

[0064] In some embodiments, each R or L, or at least one of R or L (e.g., in formula (I), (II), or (IIa)) is halo. In particular, the precursor can be a metal halide. Non-limiting metal halides include SnBr4 , SnCl 4 , SnI 4 , and SbCl 3 may be mentioned.

[0065] In some embodiments, each R or L, or at least one R or L (e.g., in formula (I), (II), or (IIa)) can contain a nitrogen atom. In certain embodiments, one or more Rs or Ls can be an optionally substituted amino, an optionally substituted monoalkylamino (e.g., -NR 1 H, R 1 is an optionally substituted alkyl), an optionally substituted dialkylamino (e.g., -NR 1 R 2 , each R 1 and R 2 are independently an optionally substituted alkyl), or an optionally substituted bis(trialkylsilyl)amino. Non-limiting R and L substituents can include, for example, -NMe 2 , -NHMe, -NEt 2 , -NHEt, -NMeEt, -N(t-Bu)-[CHCH 3 2 -N(t-Bu)-(tbba), -N(SiMe 3 ) 2 , and -N(SiEt 3 ) 2 may be mentioned.

[0066] In some embodiments, each R or L, or at least one R or L (e.g., in formula (I), (II), or (IIa)) can contain a silicon atom. In certain embodiments, one or more Rs or Ls can be an optionally substituted trialkylsilyl or an optionally substituted bis(trialkylsilyl)amino. Non-limiting R or L substituents can include, for example, -SiMe 3 , -SiEt 3 , -N(SiMe 3 ) 2 , and -N(SiEt 3 ) 2 may be mentioned.​

[0067] In some embodiments, each R or L, or at least one R or L (e.g., in Formula (I), (II), or (IIa)) can contain an oxygen atom. In certain embodiments, one or more Rs or Ls can be optionally substituted alkoxy or optionally substituted alkanoyloxy. Non-limiting R or L substituents include, for example, methoxy, ethoxy, isopropoxy (i-PrO), t-butoxy (t-BuO), acetate (-OC(O)-CH 3 ), and -O=C(CH 3 )-CH=C(CH 3 )-O-(acac).

[0068] Any formula herein can contain one or more neutral ligands. Non-limiting neutral ligands include optionally substituted amines (e.g., NR 3 or R 2 N-Ak-NR 2 , each R can independently be H, optionally substituted alkyl, optionally substituted hydrocarbyl, or optionally substituted aryl, and Ak is optionally substituted alkylene), optionally substituted phosphines (e.g., PR 3 or R 2 P-Ak-PR 2 , each R can independently be H, optionally substituted alkyl, optionally substituted hydrocarbyl, or optionally substituted aryl, and Ak is optionally substituted alkylene), optionally substituted ethers (e.g., OR 2 , each R can independently be H, optionally substituted alkyl, optionally substituted hydrocarbyl, or optionally substituted aryl), optionally substituted alkyl, optionally substituted alkene, optionally substituted alkyne, optionally substituted benzene, oxo, or carbon monoxide.

[0069] Any formula in this specification can include one or more polydentate (e.g., bidentate) ligands. Non-limiting polydentate ligands include diketonates (e.g., acetylacetonate (acac) or -OC(R 1 )-Ak-(R 1 )CO- or -OC(R 1 )-C(R 2 )-(R 1 )CO-), bidentate chelating dinitrogen (e.g., -N(R 1 )-Ak-N(R 1 )- or -N(R 3 )-CR 4 -CR 2 =N(R 1 )-), aromatic (e.g., -Ar-), amidinate (e.g., -N(R 1 )-C(R 2 )-N(R 1 )-), aminoalkoxide (e.g., -N(R 1 )-Ak-O- or -N(R 1 ) 2 -Ak-O-), diazadienyl (e.g., -N(R 1 )-C(R 2 )-C(R 2 )-N(R 1 )-), cyclopentadienyl, pyrazolate, optionally substituted heterocyclyl, optionally substituted alkylene, or optionally substituted heteroalkylene. In certain embodiments, each R 1 is independently H, optionally substituted alkyl, optionally substituted haloalkyl, or optionally substituted aryl, each R 2 is independently H or optionally substituted alkyl, R 3 and R 4 together form an optionally substituted heterocyclyl, Ak is optionally substituted alkylene, and Ar is optionally substituted arylene.

[0070] In certain embodiments, the precursor includes tin. In some embodiments, the tin precursor is SnR or SnR 2 or SnR4 or R 3 SnSnR 3 and each R is independently H, halo, optionally substituted C 1-12 alkyl, optionally substituted C 1-12 alkoxy, optionally substituted amino (e.g., -NR 1 R 2 ), optionally substituted C 2-12 alkenyl, optionally substituted C 2-12 alkynyl, optionally substituted C 3-8 cycloalkyl, optionally substituted aryl, cyclopentadienyl, optionally substituted bis(trialkylsilyl)amino (e.g., -N(SiR 1 R 2 R 3 )) 2 ), optionally substituted alkanoyloxy (e.g., acetate), diketonate (e.g., -OC(R 1 )-Ak-(R 2 )CO-), or bidentate chelating dinitrogen (e.g., -N(R 1 )-Ak-N(R 1 ))). In certain embodiments, each R 1 , R 2 , and R 3 is independently H or C 1-12 alkyl (e.g., methyl, ethyl, isopropyl, t-butyl, or neopentyl), and Ak is optionally substituted C 1-6 alkylene. In certain embodiments, each R is independently halo, optionally substituted C 1-12 alkoxy, optionally substituted amino, optionally substituted aryl, cyclopentadienyl, or diketonate. Non-limiting tin precursors include SnF 2 , SnH 4 , SnBr 4 , SnCl 4 , SnI 4 , tetramethyltin (SnMe 4 ), tetraethyltin (SnEt 4 ), trimethyltin chloride (SnMe 3(Cl), dimethyltin dichloride (SnMe 2 Cl 2 ), methyltin trichloride (SnMeCl 3 ), tetraallyltin, tetravinyltin, hexaphenylditin(IV) (Ph 3 Sn - SnPh 3 , Ph is phenyl), dibutyldiphenyltin (SnBu 2 Ph 2 ), trimethyl(phenyl)tin (SnMe 3 Ph), trimethyl(phenylethynyl)tin, tricyclohexyltin hydride, tributyltin hydride (SnBu 3 H), dibutyltin diacetate (SnBu 2 (CH 3 COO) 2 ), tin(II) acetylacetonate (Sn(acac) 2 ), tributyltin ethoxide (SnBu 3 (OEt)), dibutyltin dimethoxide (SnBu 2 (OMe) 2 , tributyltin methoxide (SnBu 3 (OMe)), tin(IV) tert - butoxide (Sn(t - BuO) 4 ), n - butyltin tributoxide (Sn(n - Bu)(t - BuO) 3 ), tetrakis(dimethylamino)tin (Sn(NMe 2 ) 4 ), tetrakis(ethylmethylamino)tin (Sn(NMeEt) 4 ), tetrakis(diethylamino)tin(IV) (Sn(NEt 2 ) 4 ), (dimethylamino)trimethyltin(IV) (Sn(Me) 3 (NMe 2 ), Sn(i - Pr)(NMe 2 ) 3 , Sn(n - Bu)(NMe 2 ) 3 , Sn(s - Bu)(NMe 2 ) 3 , Sn(i - Bu)(NMe 2 ) 3 , Sn(t - Bu)(NMe2 ) 3 、Sn(t-Bu) 2 (NMe 2 ) 2 、Sn(t-Bu)(NEt 2 ) 3 、Sn(tbba), Sn(II)(1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannolidine-2-ylidene), or bis[bis(trimethylsilyl)amino]tin (Sn[N(SiMe 3 ) 2 ) 2 ) are included.

[0071] In other embodiments, the precursor comprises bismuth such as BiR 3 , where each R is independently halo, optionally substituted C 1-12 alkyl, mono-C 1-12 alkylamino (e.g., -NR 1 H), di-C 1-12 alkylamino (e.g., -NR 1 R 2 ), optionally substituted aryl, optionally substituted bis(trialkylsilyl)amino (e.g., -N(SiR 1 R 2 R 3 ), or diketonate (e.g., -OC(R 2 )-Ak-(R 4 )CO-). In certain embodiments, each R 5 , R 1 , and R 2 are independently C 3 alkyl (e.g., methyl, ethyl, isopropyl, t-butyl, or neopentyl), and each R 1-12 and R 4 and R 5 are independently H or optionally substituted C 1-12 alkyl (e.g., methyl, ethyl, isopropyl, t-butyl, or neopentyl). Non-limiting bismuth precursors include BiCl 3 , BiMe 3 , BiPh 3 , Bi(NMe 2 )3 , Bi[N(SiMe 3 ) 2 3 , and Bi(thd) 3 are included, where thd is 2,2,6,6 - tetramethyl - 3,5 - heptanedionate.

[0072] In other embodiments, the precursor includes tellurium such as TeR 2 or TeR 4 , and each R is independently halo, optionally substituted C 1-12 alkyl (e.g., methyl, ethyl, isopropyl, t - butyl, and neopentyl), optionally substituted C 1-12 alkoxy, optionally substituted aryl, hydroxyl, oxo, or optionally substituted trialkylsilyl. Non - limiting tellurium precursors include dimethyltellurium (TeMe 2 ), diethyltellurium (TeEt 2 ), di(n - butyl)tellurium (Te(n - Bu) 2 ), di(isopropyl)tellurium (Te(i - Pr) 2 ), di(t - butyl)tellurium (Te(t - Bu) 2 ), t - butyltellurium hydride (Te(t - Bu)(H)), Te(OEt) 4 , bis(trimethylsilyl)tellurium (Te(SiMe 3 ) 2 ), and bis(triethylsilyl)tellurium (Te(SiEt 3 ) 2 ).

[0073] The precursor can include antimony such as SbR 3 , and each R is independently halo, optionally substituted C 1-12 alkyl (e.g., methyl, ethyl, isopropyl, t - butyl, and neopentyl), optionally substituted C 1-12 alkoxy, or optionally substituted amino (e.g., - NR 1 R 2 , each R 1 and R 2 ​is, independently, H or optionally substituted C 1-12 alkyl). Non-limiting antimony precursors include SbCl 3 , Sb(OEt) 3 , Sb(On-Bu) 3 , and Sb(NMe 2 ) 3 .

[0074] Other precursors include indium precursors such as InR 3 , where each R is, independently, halo, optionally substituted C 1-12 alkyl (e.g., methyl, ethyl, isopropyl, t-butyl, and neopentyl), or diketonate (e.g., -OC(R 4 )-Ak-(R 5 )CO-, where each R 4 and R 5 is, independently, H or C 1-12 alkyl). Non-limiting indium precursors include InCp, where Cp is cyclopentadienyl, InCl 3 , InMe 3 , In(acac) 3 , In(CF 3 COCHCOCH 3 ) 3 , and In(thd) 3 .

[0075] The precursor can contain iodine such as RI, where R is iodine (I), or optionally substituted C 1-12 alkyl, or periodate. Non-limiting iodine precursors include iodine gas (I 2 ), diiodomethane (CH 2 I 2 ), and periodate.

[0076] Still other precursors and non-limiting substituents are described herein. For example, the precursor can be any having the structures of formulas (I), (II), and (IIa) described above, or formulas (III), (IV), (V), (VI), (VII), or (VIII) described below. Any of the substituents M, R, X, or L described herein can be used in any of formulas (I), (II), (IIa), (III), (IV), (V), (VI), (VII), or (VIII).

[0077] The various atoms present in the precursor and / or the counter-reagent can be supplied into the gradient film. In some embodiments of the techniques described herein, a non-limiting strategy that can further improve the hydrophobic contrast in the photoresist film by forming a film in which the film composition is vertically inclined, resulting in depth-dependent hydrophobic properties. In a homogeneous photoresist, the hydrophobic properties of the film are the same throughout most of the film and the entire upper surface of the film. By increasing the hydrophobicity of the film at the upper part of the film compared to the bottom of the film (close to the substrate), it becomes possible to more effectively avoid dissolution of the film through the upper surface by an aqueous acid solution.

[0078] Strategies for manipulating the vertical composition gradient in the photoresist film are particularly applicable to dry deposition methods such as CVD and ALD and can be achieved by adjusting the flow rate ratio between different reagents during deposition. Types of composition gradients that can be manipulated include the ratio between different R or L ligands for the precursor, the use of different precursors having more hydrophobic R ligands, the proportion of the counter-reagent containing a carbon-containing element, and combinations of the above.

[0079] In addition, such a composition gradient can contain more bulky terminal substituents located on the upper surface of the film. For example, in the case of an Sn-based resist, it is possible to incorporate a tin precursor having two or more R groups on the upper surface, whereby additional hydrophobic R groups are present on the upper surface of the photoresist film.

[0080] In one embodiment, the gradient film can include a first concentration of carbon content in the upper portion of the film (far from the substrate) and a second concentration of carbon content in the bottom portion of the film (close to the substrate), and the first concentration value and the second concentration value are different. In one example, the first concentration is higher than the second concentration. Non-limiting gradients include linear gradients, exponential gradients, sigmoid gradients, and the like. In certain embodiments, the gradient density film of the EUV-responsive organic moiety can provide more homogeneous film properties in the EUV exposure area at all depths within the film, thereby improving the development process, improving EUV sensitivity, and / or improving patterning quality (e.g., improving LWR and / or LER).

[0081] Such gradient films can be formed by using any of the precursors (e.g., tin or non-tin precursors) and / or reverse reactants described herein. Further other films, methods, precursors, and other compounds are described in U.S. Provisional Patent Application No. 62 / 909,430, filed Oct. 2, 2019, and International Application No. PCT / US20 / 53856, filed Oct. 1, 2020 and published as International Publication No. WO2021 / 067632, each entitled "SUBSTRATE SURFACE MODIFICATION WITH HIGH EUV ABSORBERS FOR HIGH PERFORMANCE EUV PHOTORESISTS", and International Application No. PCT / US20 / 70172, filed Jun. 24, 2020 and published as International Publication No. WO2020 / 264557, entitled "PHOTORESIST WITH MULTIPLE PATTERNING RADIATION-ABSORBING ELEMENTS AND / OR VERTICAL COMPOSITION GRADIENT", and the above disclosures related at least to the composition, deposition, and patterning of a directly photopatternable metal oxide film for forming an EUV resist mask are hereby incorporated by reference herein.

[0082] The various atoms present in the precursor and / or the reverse reactant can be supplied into the capping layer, and the capping layer is disposed on any useful layer or structure. The capping layer can have any useful thickness (e.g., any thickness described herein including from about 0.1 nm to about 5 nm).

[0083] Furthermore, two or more different precursors can be used within each layer (e.g., film or capping layer). For example, an alloy can be formed using two or more of any of the metal-containing precursors herein. In one non-limiting example, tin telluride can be RTeH, RTeD, or TeR 2 with -NR 2 ligand-containing tin precursor, where R is alkyl, particularly t-butyl or i-propyl. In another example, a metal telluride can be formed by using a first precursor containing an alkoxy or halo ligand (e.g., SbCl 3 ) together with a tellurium-containing precursor containing a trialkylsilyl ligand (e.g., bis(trimethylsilyl)tellurium).

[0084] Further exemplary EUV-sensitive materials, as well as processing methods and apparatuses, are described in U.S. Patent No. 9,996,004, International Patent Publication No. WO2020 / 102085, and International Patent Publication No. WO2019 / 217749, each of which is incorporated herein by reference in its entirety.

[0085] As described herein, the films, layers, and methods herein can be used with any useful precursor. In some cases, the precursor has the following formula (III): MX n (III) and includes a metal halide, depending on the selection of M, M is a metal, X is a halo, and n is from 2 to 4. Exemplary metals for M include Sn, Te, Bi, or Sb. Exemplary metal halides include SnBr 4 , SnCl4 , SnI 4 , and SbCl 3 may be mentioned.

[0086] Another non-limiting precursor is of formula (IV): MR n (IV) includes a structure having M is a metal, each R is independently H, optionally substituted alkyl, amino (e.g., -NR 2 , each R is independently alkyl), optionally substituted bis(trialkylsilyl)amino (e.g., -N(SiR 3 ), each R is independently alkyl), or optionally substituted trialkylsilyl (e.g., -SiR 2 , each R is independently alkyl), and depending on the choice of M, n is 2 to 4. Exemplary metals for M include Sn, Te, Bi, or Sb. The alkyl group may be C 3 H n and n is 1, 2, 3, or more. Exemplary organometallic agents include SnMe 2n+1 , SnEt 4 , TeR 4 , RTeR, tert-butyl telluride hydride (Te(t-Bu)(H)), dimethyl telluride (TeMe n ), di(tert-butyl) telluride (Te(t-Bu) 2 ), di(isopropyl) telluride (Te(i-Pr) 2 ), bis(trimethylsilyl) telluride (Te(SiMe 2 ), bis(triethylsilyl) telluride (Te(SiEt 3 ), tris(bis(trimethylsilyl)amide) bismuth (Bi[N(SiMe 2 ), bis(trimethylsilyl)amide) bismuth (Bi[N(SiMe 3 ), tris(bis(trimethylsilyl)amide) bismuth (Bi[N(SiMe 2 ), tris(bis(trimethylsilyl)amide) bismuth (Bi[N(SiMe 3 ), tris(bis(trimethylsilyl)amide) bismuth (Bi[N(SiMe 2 3 ), Sb(NMe 2 ), etc. may be mentioned. 3

[0087] Another non-limiting precursor is the following formula (V):​ ML n (V) and can include a capping agent having M is a metal, and each L is independently optionally substituted alkyl, amino (e.g., -NR 1 R 2 , R 1 and R 2 each can be H or alkyl as described herein), alkoxy (e.g., -OR where R is alkyl as described herein), halo, or other organic substituents, and depending on the choice of M, n is 2 - 4. Exemplary metals for M include Sn, Te, Bi, or Sb. Exemplary ligands include dialkylamino (e.g., dimethylamino, methylethylamino, and diethylamino), alkoxy (e.g., t-butoxy and isopropoxy), halo (e.g., F, Cl, Br, and I), or other organic substituents (e.g., acetylacetone or N 2 ,N 3 -di-tert-butyl-butane-2,3-diamino). Non-limiting capping agents include SnCl 4 , SnI 4 , Sn(NR 2 ) 4 , where each R is independently methyl or ethyl, or Sn(t-BuO) 4 . In some embodiments, multiple types of ligands are present.

[0088] The precursor can include a hydrocarbyl-substituted capping agent having the following formula (VI): R n MX m (VI) and can include a hydrocarbyl-substituted capping agent having M is a metal, and R is a C having beta hydrogen 2-10It is alkyl or substituted alkyl, and X is a suitable leaving group by reaction with the hydroxyl group of the exposed hydroxyl group. In various embodiments, as long as m > 0 (or m ≥ 1), n = 1 to 3, and m = 4 - n, 3 - n, or 2 - n. For example, R can be t-butyl, t-pentyl, t-hexyl, cyclohexyl, isopropyl, isobutyl, sec-butyl, n-butyl, n-pentyl, n-hexyl, or derivatives thereof having a heteroatom substituent at the beta position. Suitable heteroatoms include halogen (F, Cl, Br, or I), or oxygen (-OH or -OR). X can be dialkylamino (e.g., dimethylamino, methylethylamino, or diethylamino), alkoxy (e.g., t-butoxy, isopropoxy), halo (e.g., F, Cl, Br, or I), or another organic ligand. Examples of hydrocarbyl-substituted capping agents include t-butyltris(dimethylamino)tin (Sn(t-Bu)(NMe 2 ) 3 ), n-butyltris(dimethylamino)tin (Sn(n-Bu)(NMe 2 ) 3 ), t-butyltris(diethylamino)tin (Sn(t-Bu)(NEt 2 ) 3 ), di(t-butyl)di(dimethylamino)tin (Sn(t-Bu) 2 (NMe 2 ) 2 ), sec-butyltris(dimethylamino)tin (Sn(s-Bu)(NMe 2 ) 3 ), n-pentyltris(dimethylamino)tin (Sn(n-pentyl)(NMe 2 ) 3 ), i-butyltris(dimethylamino)tin (Sn(i-Bu)(NMe 2 ) 3 ), i-propyltris(dimethylamino)tin (Sn(i-Pr)(NMe 2 ) 3 ), t-butyltris(t-butoxy)tin (Sn(t-Bu)(t-BuO) 3 ), n-butyl(tris(t-butoxy)tin (Sn(n-Bu)(t-BuO)3 ) or isopropyltris(t-butoxy)tin (Sn(i-Pr)(t-BuO) 3 ) are mentioned.

[0089] In various embodiments, the precursor contains at least one alkyl group on each metal atom that can withstand a gas-phase reaction, and other ligands or ions coordinated to the metal atom can be substituted by a reverse reactant. Thus, another non-limiting precursor is of formula (VII): M a R b L c (VII) and includes an organometallic agent having M is a metal, R is an optionally substituted alkyl, L is a ligand, ion, or other moiety that reacts with the reverse reactant, a ≧ 1, b ≧ 1, and c ≧ 1. In certain embodiments, a = 1 and b + c = 4. In some embodiments, M is Sn, Te, Bi, or Sb. In certain embodiments, each L is independently amino (e.g., -NR 1 R 2 、R 1 and R 2 each can be H or alkyl as described herein), alkoxy (e.g., -OR, where R is alkyl as described herein), or halo (e.g., F, Cl, Br, or I). Exemplary agents include SnMe 3 Cl, SnMe 2 Cl 2 , SnMeCl 3 , SnMe(NMe 2 ) 3 , SnMe 2 (NMe 2 ) 2 , SnMe 3 (NMe 2 ) and the like.

[0090] In other embodiments, the non-limiting precursor is of formula (VIII): M a L c (VIII) comprising an organometallic agent having M is a metal, L is a ligand, ion, or other moiety that reacts with a counteragent, a ≧ 1, and c ≧ 1. In certain embodiments, c = n - 1, where n is 2, 3, or 4. In some embodiments, M is Sn, Te, Bi, or Sb. The counteragent preferably has the ability to replace a reactive partial ligand or ion (e.g., L in the formulas herein) such that at least two metal atoms are linked via a chemical bond.

[0091] In any of the embodiments herein, R can be optionally substituted alkyl (e.g., C 1-10 alkyl). In one embodiment, the alkyl is substituted with one or more halos (e.g., halo-substituted C 1-10 alkyl) containing one, two, three, four, or more halos such as F, Cl, Br, or I. Exemplary R substituents preferably include C n H 2n+1 where n ≧ 3, and C n F x H( 2n+1-x ) where 2n + 1 ≧ x ≧ 1. In various embodiments, R has at least one beta hydrogen, beta halogen, or beta fluorine. For example, R may be selected from the group consisting of i-propyl, n-propyl, t-butyl, i-butyl, n-butyl, sec-butyl, n-pentyl, i-pentyl, t-pentyl, sec-pentyl, and mixtures thereof.

[0092] In any of the embodiments herein, L is an M-OH moiety, such as amino (e.g., -NR 1 R 2 , R 1 and R 2Each of which may be H or alkyl as described anywhere herein), alkoxy (e.g., -OR, where R is alkyl as described anywhere herein), carboxylate, halo (e.g., F, Cl, Br, or I), and any moiety that can be readily substituted by a counter-reagent to produce a moiety selected from the group consisting of these and mixtures thereof.

[0093] The counter-reagent preferably has the ability to displace a reactive moiety, ligand, or ion (e.g., L in the formulas herein) so as to link at least two metal atoms via a chemical bond. Exemplary counter-reagents include oxygen-containing counter-reagents such as oxygen (O 2 ), ozone (O 3 ), water, peroxide (e.g., hydrogen peroxide), oxygen plasma, water plasma, alcohol, dihydroxy alcohol, polyhydroxy alcohol, fluorinated dihydroxy alcohol, fluorinated polyhydroxy alcohol, fluorinated glycol, formic acid, and other sources of hydroxyl moieties, and combinations thereof. In various embodiments, the counter-reagent reacts with the precursor by forming an oxygen bridge between adjacent metal atoms. Other potential counter-reagents include hydrogen sulfide and hydrogen disulfide, which can crosslink metal atoms via sulfur bridges, and bis(trimethylsilyl)tellurium, which can crosslink metal atoms via tellurium bridges. In addition, hydrogen iodide may be utilized to incorporate iodine into the film.

[0094] Still other non-limiting counter-reagents include chalcogenide precursors having the formula ZR 2 where Z is sulfur, selenium, or tellurium and each R is independently H, optionally substituted alkyl (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, etc.), optionally substituted alkenyl, optionally substituted aryl, optionally substituted amino, optionally substituted alkoxy, or optionally substituted trialkylsilyl.

[0095] Exemplary organometallic agents include SnMeCl 3 , (N 2 ,N 3 -di-t-butyl-butane-2,3-diamide)tin(II) (Sn(tbba)), bis(bis(trimethylsilyl)amide)tin(II), tetrakis(dimethylamino)tin(IV) (Sn(NMe 2 )) 4 ), t-butyltris(dimethylamino)tin (Sn(t-butyl)(NMe 2 )) 3 ), i-butyltris(dimethylamino)tin (Sn(i-Bu)(NMe 2 )) 3 ), n-butyltris(dimethylamino)tin (Sn(n-Bu)(NMe 2 )) 3 ), sec-butyltris(dimethylamino)tin (Sn(s-Bu)(NMe 2 )) 3 ), i-propyl(tris)dimethylaminotin (Sn(i-Pr)(NMe 2 )) 3 ), n-propyltris(diethylamino)tin (Sn(n-Pr)(NEt 2 )) 3 ), and similar alkyl(tris)(t-butoxy)tin compounds, such as t-butyltris(t-butoxy)tin (Sn(t-Bu)(t-BuO) 3 ). In some embodiments, the organometallic agent is partially fluorinated.

[0096] In some embodiments, the patterning structure can include a surface layer or film that includes exposed hydroxyl groups or a hydroxyl-terminated SnO x . Without limiting the mechanism, function, or utility of the present technology, the hydroxyl-terminated SnO x layer can be thought to provide advantages such as improved adhesion of materials deposited on the surface of the substrate and enhanced absorption of EUV (or other radiation) during patterning. The sensitivity and resolution to EUV or other irradiation can be affected by the thickness, density, and short-range charge transfer properties of the SnO xIt may depend on the properties of the layer. In various embodiments, SnO x The layer has a thickness of 0.1 nm to 20 nm, or 0.2 nm to 10 nm, or 0.5 nm to 5 nm.

[0097] In some embodiments, the hydroxyl-terminated SnO x The layer is deposited on the surface of the substrate by vapor deposition. In such a method, the deposition involves reacting Sn-X n with an oxygen-containing reactant, where X is a ligand such as dialkylamino (e.g., dimethylamino, methylethylamino, and diethylamino), alcohol (e.g., t-butoxy and isopropoxy), halogen (e.g., F, Cl, Br, and I), or other organic substituents (e.g., acetylacetone, N2,N3-di-tert-butyl-butane-2,3-diamino). For example, Sn-X n is SnCl 4 , SnI 4 , or Sn(NR 2 ) 4 where R is methyl or ethyl, or Sn(t-BuO) 4 . In some embodiments, there are multiple types of ligands. The oxygen-containing reactant may be selected from the group consisting of water, hydrogen peroxide, formic acid, alcohol, oxygen, ozone, and combinations thereof.

[0098] Suitable vapor deposition processes include chemical vapor deposition (CVD), atomic layer deposition (ALD), plasma-enhanced chemical vapor deposition (PECVD), or plasma-enhanced atomic layer deposition (PEALD). In some embodiments, the deposition is ALD in a cyclic process of depositing Sn-X n and depositing an oxygen-containing reactant. In some embodiments, the deposition is CVD by flowing Sn-X n and an oxygen-containing reactant simultaneously. SnO xUseful materials and processes herein for depositing layers are described in Nazarov et al., Atomic Layer Deposition of Tin Dioxide Nanofilms: A Review, 40 Rev. Adv. Mater. Sci. 262 (2015). SnO x The substrate can be deposited by CVD or ALD processes as described herein.

[0099] A surface activation operation can be used to activate the surface for future operations. For example, for SiO x surfaces, water or an oxygen / hydrogen plasma can be used to form hydroxyl groups on the surface. For carbon-based or hydrocarbon-based surfaces, water, hydrogen / oxygen, or CO 2 plasma, or ozone treatment can be used to form carboxylic acid / or hydroxyl groups. Such an approach can improve the adhesion of resist features to the substrate, which may in some cases be subject to peeling or lift-off in the solvents used for development.

[0100] Adhesion can also be enhanced by increasing the surface area available for interaction and inducing roughness on the substrate surface to directly improve mechanical adhesion. For example, a sputtering process using first Ar or other non-reactive ion bombardment can be used to produce a rough surface. The surface can then be terminated with the desired surface functional groups (e.g., hydroxyl and / or carboxylic acid groups) as described above. On carbon, CO 2 , O 2 , H 2 O (or H 2 and O 2A combined approach can be used to etch away a thin layer of a film having local non-uniformities using a chemically reactive oxygen-containing plasma (such as a mixture of etc.) and at the same time terminate with -OH, -OOH, or -COOH groups. This approach can be carried out with or without bias. In combination with the surface modification strategies described above, this approach can serve the dual purpose of roughening and chemically activating the substrate surface, either for direct adhesion to an inorganic metal oxide-based resist or as an intermediate surface modification for further functionalization.

[0101] The patterning structure can include any useful substrate. For example, the next wafer having a substrate surface of a desired material can be prepared, and the top material is the layer onto which the resist pattern is transferred. The choice of material can vary depending on the integration, but generally, it is desirable to select a material that can be etched with high selectivity (i.e., much faster than them) with respect to EUV resists or imaging layers. In some embodiments, the substrate is a hard mask used in lithographic etching of underlying semiconductor materials. The hard mask includes amorphous carbon (a-C), tin oxide (e.g., SnO x ), silicon oxide (e.g., SiO 2 including SiO x ), silicon oxynitride (e.g., SiO x N y ), silicon oxycarbide (e.g., SiO x C y ), silicon nitride (e.g., Si 3 N 4 ), titanium oxide (e.g., TiO 2 ), titanium nitride (e.g., TiN), tungsten (e.g., W), doped carbon (e.g., W-doped C), tungsten oxide (e.g., WO x ), hafnium oxide (e.g., HfO 2 ), zirconium oxide (e.g., ZrO 2 ), and aluminum oxide (e.g., Al 2 O 3It can include any of a variety of materials, including x . SiC x . SiO x C y . SiO x N y . SiO x C y N z ), a-Si:H, poly-Si, or SiN), or any other (generally sacrificial) film applied to facilitate the patterning process). For example, the substrate preferably contains SnO 2 such as SnO x . In various embodiments, the layer may have a thickness of 1 nm to 100 nm, or 2 nm to 10 nm.

[0102] In various embodiments, the surface (e.g., of the substrate and / or the film) contains hydroxyl groups exposed on the surface. Generally, the surface can be any surface that contains or results in an exposed hydroxyl surface. Such hydroxyl groups can be formed on the surface by surface treatment of the substrate using oxygen plasma, water plasma, or ozone. In other embodiments, the surface of the film can be treated to provide exposed hydroxyl groups onto which a capping layer can be applied. In various embodiments, the hydroxyl-terminated metal oxide layer has a thickness of 0.1 nm to 20 nm, or 0.2 nm to 10 nm, or 0.5 nm to 5 nm.

[0103] The embodiments disclosed herein describe the deposition of materials onto a substrate such as a wafer, a substrate, or other workpiece. The workpiece may be of various shapes, sizes, and materials. In this application, the terms "semiconductor wafer", "wafer", "substrate", "wafer substrate", and "partially fabricated integrated circuit" are used interchangeably. One of ordinary skill in the art will understand that the term "partially fabricated integrated circuit" can refer to a silicon wafer during any of many stages of integrated circuit fabrication. Wafers or substrates used in the semiconductor device industry may have a diameter of 200 mm, or 300 mm, or 450 mm. Unless otherwise specified, the process details recited herein (e.g., flow rates, power levels, etc.) relate to the processing of a 300 mm diameter substrate, or a processing chamber configured to process a 300 mm diameter substrate, and can be scaled appropriately depending on other substrate or chamber sizes. In addition to semiconductor wafers, other workpieces that may be used in the embodiments disclosed herein include various articles such as printed circuit boards. The processes and apparatus can be used for the fabrication of semiconductor devices, displays, and the like.

[0104] As described above, the present disclosure provides a method for a film on a semiconductor substrate, which can be patterned using EUV or other next-generation lithography techniques. The methods include those in which a polymerizable organometallic material is generated in a vapor and deposited onto the substrate. In some embodiments, dry deposition can use any useful precursor (e.g., the metal halides, capping agents, or organometallic agents described herein). In other embodiments, spin-on formulations can be used. The deposition process can include applying an EUV-sensitive material as a resist film or an EUV-sensitive film.

[0105] Such EUV-sensitive films include materials that undergo changes such as the loss of bulky pendant ligands bonded to metal atoms upon exposure to EUV. When the unexposed regions include a material rich in dense M-O-M, EUV-induced cleavage can provide intermediates that are more readily removed by a positive developer.

[0106] EUV patterning forms areas of the film with changed physical or chemical properties compared to the unexposed regions. These properties can be utilized in subsequent processing, such as dissolving either the unexposed or exposed regions, or selectively depositing material on either the exposed or unexposed regions. In some embodiments, the unexposed film has a hydrophobic surface and the exposed film has a hydrophilic surface under the conditions under which such subsequent processing is carried out (it is recognized that the hydrophilic properties of the exposed and unexposed regions are interrelated). For example, removal of the material can be carried out by exploiting differences in the chemical composition, density, and crosslinking of the film. The removal can be by wet or dry processing, as further described herein.

[0107] The thickness of the EUV-patternable film formed on the surface of the substrate can vary according to the surface characteristics, the materials used, and the processing conditions. In various embodiments, the film thickness can range from about 0.5 nm to about 100 nm. Preferably, the film has a thickness sufficient to absorb most of the EUV light under the conditions of EUV patterning. For example, the overall absorption of the resist film can be 30% or less (e.g., 10% or less, or 5% or less) so that the resist material at the bottom of the resist film is sufficiently exposed. In some embodiments, the film thickness is 10 nm to 20 nm. Without limiting the mechanisms, functions, or utilities of the present disclosure, the processes of the present disclosure are believed to be applicable to a wide variety of substrates. Further, as described above, the deposited film closely conforms to the surface features and can provide advantages when forming a mask on a substrate, such as a substrate having underlying features, without "filling" or planarizing such features.

[0108] The film can be composed of a metal oxide layer deposited in any useful manner. Such a metal oxide layer can be deposited or applied by using any EUV-sensitive material described herein, such as a precursor combined with a counter-reactant (e.g., a metal-containing precursor, a metal halide, a capping agent, or an organometallic agent). In an exemplary process, a polymeric organometallic material is formed in the gas phase or in situ on the surface of the substrate to provide the metal oxide layer. The metal oxide layer can be used as a film, an adhesion layer, or a capping layer.

[0109] Optionally, the metal oxide layer can include a hydroxyl-terminated metal oxide layer, which can be deposited by using a capping agent (e.g., any of those described herein) together with an oxygen-containing counter-reactant. Such a hydroxyl-terminated metal oxide layer can be used as an adhesion layer between two other layers, for example, between the substrate and the film and / or between the photoresist layer and the capping layer.

[0110] Exemplary deposition techniques (e.g., for films) include any of those described herein, such as ALD (e.g., thermal ALD and plasma-enhanced ALD), spin-coat deposition, PVD including co-sputtering, CVD (e.g., PE-CVD or LP-CVD), sputter deposition, e-beam deposition including e-beam co-evaporation, or combinations thereof, such as ALD using CVD components, e.g., a discontinuous ALD-like process in which the precursor and the counter-reactant are separated either in time or in space.

[0111] Further description of precursors as EUV photoresist films applicable to the present disclosure and methods for their deposition can be found in International Application No. PCT / US19 / 31618, entitled "METHODS FOR MAKING EUV PATTERNABLE HARD MASKS", published as International Publication No. WO2019 / 217749 on May 9, 2019. The thin film can include optional materials in addition to the precursor and the reverse reactant, and can modify the chemical or physical properties of the film, such as modifying the sensitivity of the film to EUV or enhancing the etching resistance. Such optional materials may be introduced, for example, by doping during vapor phase formation before deposition onto the substrate, during deposition onto the substrate, and / or after deposition of the film. In some embodiments, introducing a gentle remote H 2 plasma can, for example, replace some Sn-L bonds with Sn-H, thereby increasing the reactivity of the resist under EUV. In other embodiments, CO 2 is introduced to replace some Sn-O bonds with Sn-CO 3 bonds, which can make it possible to have higher resistance to wet development.

[0112] Generally, the method can include mixing a vapor stream of a precursor (e.g., a metal-containing precursor such as an organometallic agent) with an optional vapor stream of a reverse reactant to form a polymerized organometallic material, and depositing the organometallic material onto the surface of a semiconductor substrate. In some embodiments, the polymerized organometallic material can be formed by mixing the precursor and an optional reverse reactant. As will be understood by those skilled in the art, the mixing and deposition aspects of the process may be simultaneous in a substantially continuous process.

[0113] In an exemplary continuous CVD process, in separate inlet paths, two or more gas streams of precursors and optional reactants are introduced into the deposition chamber of the CVD apparatus, where they mix and react in the gas phase to form an aggregated polymer material or film (e.g., via metal-oxygen-metal bond formation) on the substrate. The gas streams can be introduced, for example, using separate injection inlets or a dual-plenum showerhead. The apparatus is configured such that the flows of the precursors and optional reactants are mixed within the chamber, thereby enabling the precursors and optional reactants to react to form a polymerized organometallic material or film (e.g., a metal oxide coating or an aggregated polymer material via metal-oxygen-metal bond formation, etc.).

[0114] To deposit a metal oxide, the CVD process is generally performed at a reduced pressure such as 0.1 Torr to 10 Torr. In some embodiments, the process is performed at a pressure of 1 Torr to 2 Torr. The temperature of the substrate is preferably lower than the temperature of the reactant stream. For example, the substrate temperature can be 0 °C to 250 °C, or ambient temperature (e.g., 23 °C) to 150 °C.

[0115] To deposit an aggregated polymer material, the CVD process is generally performed at a reduced pressure such as 10 mTorr to 10 Torr. In some embodiments, the process is performed at 0.5 to 2 Torr. The temperature of the substrate is preferably below the temperature of the reactant stream. For example, the substrate temperature can be 0 °C to 250 °C, or ambient temperature (e.g., 23 °C) to 150 °C. In various processes, the deposition of the polymerized organometallic material onto the substrate occurs at a rate inversely proportional to the surface temperature. Without limiting the mechanism, function, or utility of the present disclosure, the product from such a gas-phase reaction is thought to become heavier in molecular weight as metal atoms are cross-linked by the reactant and then either condensed or, in some cases, deposited onto the substrate. In various embodiments, the steric hindrance of bulky alkyl groups further prevents the formation of a densely packed network, resulting in a low-density film with increased porosity.

[0116] A potential advantage of using a dry deposition method is that it is easy to adjust the composition of the film according to growth. In a CVD process, this can be achieved by changing the relative flow rates of the first and second precursors during deposition. The deposition can be carried out at a pressure of 30 °C to 200 °C, 0.01 Torr to 100 Torr, more typically about 0.1 Torr to 10 Torr.

[0117] A film (e.g., a metal oxide coating or an aggregated polymer material via formation of a metal-oxygen-metal bond, etc.) can also be deposited by an ALD process. For example, the precursor and an optional reverse reactant are introduced at separate times representing an ALD cycle. The precursor reacts on the surface and forms up to a single layer of material at a time per cycle. This can enable excellent control over the uniformity of the film thickness across the surface. The ALD process is generally carried out at a reduced pressure such as 0.1 Torr to 10 Torr. In some embodiments, the process is carried out at 1 Torr to 2 Torr. The substrate temperature can be 0 °C to 250 °C, or ambient temperature (e.g., 23 °C) to 150 °C. The process can be a thermal process, or preferably, a plasma-assisted deposition.

[0118] Any of the deposition methods herein can be modified to allow for the use of two or more different precursors. In one embodiment, the precursors can contain the same metal but different ligands. In another embodiment, the precursors can contain different metal groups. In one non-limiting example, an alternating flow of various volatile precursors can be used to provide a mixed metal-containing layer, such as the use of a metal alkoxide precursor having a first metal (e.g., Sn) and a silyl-based precursor having a different second metal (e.g., Te).

[0119] The processes herein can be used to achieve surface modification. In some iterations, the vapor of the precursor can be passed over the wafer. The wafer can be heated to provide the thermal energy for the reaction to proceed. In some iterations, the heating can be from about 50 °C to about 250 °C. Optionally, pulses of the precursor separated by a pump and / or purge step may be used. For example, a first precursor may be pulsed between pulses of a second precursor pulse, resulting in ALD or ALD-like growth. In other cases, both precursors may be flowed simultaneously. Examples of elements useful for surface modification include I, F, Sn, Bi, Sb, Te, and oxides or alloys of these compounds.

[0120] The processes herein can be used to deposit thin metal oxides or metals by ALD or CVD. Examples include tin oxide (SnO x ), bismuth oxide (BiO x ), and Te. Following deposition, the film can be capped with an alkyl-substituted precursor in the form of M a R b L c . A reverse reactant can be used to better remove the ligands, and multiple cycles can be repeated to ensure complete saturation of the substrate surface. Next, the surface is ready for depositing an EUV-sensitive film. One possible method is to generate a thin film of SnO x . Possible chemistries include growth of SnO 2 by circulating a reverse reactant such as tetrakis(dimethylamino)tin and water or O 2 plasma. After growth, a capping agent can be used. For example, the vapor of isopropyltris(dimethylamino)tin may be flowed over the surface.

[0121] The deposition process can be used on any useful surface. As referred to herein, a "surface" is a surface on which the film of the present technology is deposited, or a surface that is exposed to EUV during processing. Such a surface can exist on a substrate (e.g., on which a film is deposited), or on a film (e.g., on which a capping layer can be deposited).

[0122] The deposition process can be used on any useful surface. As referred to herein, a "surface" is a surface on which the film of the present technology is deposited, or a surface that is exposed to EUV during processing. Such a surface can exist on a substrate (e.g., on which a film is deposited), or on a film (e.g., on which a capping layer can be deposited).

[0123] Such underlying topographical features can include regions where material has been removed (e.g., by etching) or regions where material has been added (e.g., by deposition) during processing prior to performing the methods of this technology. Such preprocessing can include the methods of this technology or other processing methods in an iterative process, whereby two or more layers of features are formed on a substrate. Without limiting the mechanisms, functions, or utilities of the present disclosure, in some embodiments, the methods of the present disclosure are believed to provide advantages such as conforming the films of the present disclosure to underlying features without "filling" or planarizing such features, and the ability to deposit films on a wide variety of material surfaces.

[0124] Exposure of Metal-Containing Resist Materials The photoresist film may be exposed to radiation. The photoresist film is exposed to radiation according to a desired pattern to form exposed and unexposed regions of the photoresist film. Exposure changes the chemical composition and crosslinking of the photoresist film, resulting in a contrast in the etching selectivity that can be utilized in subsequent development.

[0125] EUV exposure of the film can provide an EUV exposure region having activated reaction centers containing metal atoms (M), which are brought about by EUV-mediated cleavage events. Such reaction centers can include dangling metal bonds, M-H groups, cleaved M-ligand groups, dimerized M-M bonds, or M-O-M bridges.

[0126] EUV exposure can have a wavelength in the range of about 10 nm to about 20 nm, such as 10 nm to 15 nm, such as 13.5 nm, in a vacuum atmosphere. In particular, patterning can provide EUV exposure regions and non-EUV exposure regions and form a pattern. In some embodiments, such patterning includes a radiation dose of about 1 to 50 mJ / cm 2 2, 1 to 40 mJ / cm 2 2, 1 to 30 mJ / cm 2 2, 1 to 20 mJ / cm 2 2, or 1 to 10 mJ / cm 2 2.

[0127] The present disclosure can include patterning using EUV, as well as DUV or e-beam. In such patterning, the radiation is focused on one or more regions of the imaging layer. The exposure can be performed such that the imaging layer film includes one or more regions that are not exposed to the radiation. The resulting imaging layer can include a plurality of exposed and non-exposed regions and form a pattern that corresponds to the formation of transistors or other features of a semiconductor device, which is formed by adding material to or removing material from the substrate in subsequent processing of the substrate. EUV, DUV, and e-beam radiation methods and apparatuses useful herein include methods and apparatuses known in the art.

[0128] In some EUV lithography techniques, an organic hard mask (e.g., an ashing-capable hard mask of PECVD amorphous hydrogenated carbon) is patterned using a photoresist process. During photoresist exposure, EUV radiation is absorbed by the resist and the underlying substrate, generating high-energy photoelectrons (e.g., about 100 eV), which in turn generate a cascade of low-energy secondary electrons (e.g., about 10 eV) that diffuse laterally by several nanometers. These electrons increase the degree of chemical reaction within the resist and increase its EUV dose sensitivity. However, an essentially random secondary electron pattern is superimposed on the optical image. This unwanted secondary electron exposure results in a loss of resolution, observable line edge roughness (LER), and linewidth variations in the patterned resist. These defects are replicated in the patterned material during subsequent pattern transfer etching.

[0129] Disclosed herein are vacuum integrated metal hard mask processes and related vacuum integrated hardware that combine film formation (deposition / condensation) and photolithography to significantly improve EUV lithography (EUVL) performance, e.g., reduce line edge roughness.

[0130] In various embodiments described herein, a deposition (e.g., condensation) process (e.g., ALD or MOCVD performed in a PECVD tool such as a Lam Vector®) is used to form a thin film of a metal-containing film, such as a photosensitive metal salt or a metal-containing organic compound (organometallic compound), that has strong absorption at EUV (e.g., at a wavelength of about 10 nm to 20 nm), e.g., at the wavelength of an EUVL light source (e.g., 13.5 nm = 91.8 eV). This film photodecomposes upon EUV exposure to form a metal mask that is the pattern transfer layer during subsequent etching (e.g., in a conductor etch tool such as a Lam 2300® Kiyo®).

[0131] Following deposition, the EUV-patternable thin film is patterned, in some cases under relatively high vacuum, by exposure to a beam of EUV light. In the case of EUV exposure, the metal-containing film is deposited in a chamber integrated with a lithography platform (e.g., a wafer stepper such as the TWINSCAN NXE:3300B® platform supplied by ASML in Veldhoven, Netherlands) so as not to react prior to exposure and can be transferred under vacuum. Integration with the lithography tool is facilitated by the fact that EUVL also requires a significantly reduced pressure, taking into account the strong light absorption of incident photons by ambient gases such as H 2 O, O 2 Other embodiments, the photosensitive metal film deposition and EUV exposure can be performed in the same chamber. The development process

[0132] Developing the photoresist film selectively removes the exposed areas compared to the unexposed areas (i.e., positive development) or selectively removes the unexposed areas compared to the exposed areas (i.e., negative development). Development of the photoresist film forms a patterned photoresist mask. Development can proceed using wet or dry chemicals. The EUV-exposed or unexposed areas can be removed by any useful development process. In one embodiment, the EUV-exposed areas can have activated reaction centers such as dangling metal bonds, M-H groups, or dimerized M-M bonds. In other embodiments, the EUV-exposed areas are removed using wet development.

[0133] The EUV-exposed or unexposed areas can be removed by any useful development process. In one embodiment, the EUV-exposed areas can have activated reaction centers such as dangling metal bonds, M-H groups, or dimerized M-M bonds. In other embodiments, the EUV-exposed areas are removed using wet development.

[0134] In certain embodiments, a wet development process is used to remove the EUV exposure area and provide a positive photoresist. Exemplary non-limiting wet developments include the use of developers (e.g., aqueous acidic developers, non-aqueous acidic developers, or acidic developers in organic solvents) containing halides (e.g., HF, HCl, or HBr), organic acids (e.g., formic acid, acetic acid, oxalic acid, or citric acid), or organic halide compounds (e.g., organic fluorine compounds containing trifluoroacetic acid, organic chlorine compounds, organic bromine compounds, or organic iodine compounds), or the use of organic developers such as ketones (e.g., 2-heptanone, cyclohexanone, or acetone), esters (e.g., γ-butyrolactone or ethyl 3-ethoxypropionate (EEP)), alcohols (e.g., isopropyl alcohol (IPA)), or ethers such as glycol ethers (e.g., propylene glycol methyl ether (PGME) or propylene glycol methyl ether acetate (PGMEA)), and combinations thereof. Other acids (e.g., aqueous acid solutions) are described herein.

[0135] Other development methodologies include aqueous developers, non-aqueous developers, alkaline developers (e.g., aqueous alkaline developers or non-aqueous alkaline developers), such as ammonium, e.g., ammonium hydroxide ( 4 ) + [OH] - ), ammonium-based ionic liquids, e.g., tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), or other quaternary alkylammonium hydroxides, organic amines, e.g., mono-, di-, and tri-organic amines (e.g., dimethylamine, diethylamine, ethylenediamine, triethylenetetramine), or alkanolamines, e.g., monoethanolamine, diethanolamine, triethanolamine, or diethylene glycolamine. In other embodiments, the alkaline developer is a nitrogen-containing base, e.g., of the formula R N1 NH 2, R N1 R N2 NH, R N1 R N2 R N3 N, or R N1 R N2 R N3 R N4 N + X N1- can include a compound having, R N1 , R N2 , R N3 , and R N4 each of which is independently an organic substituent (e.g., optionally substituted alkyl, optionally substituted hydroxyalkyl, or any of those described herein), or two or more organic substituents that can be joined together, X N1- is OH - , F - , Cl - , Br - , I - , or other quaternary ammonium cation species known in the art. These bases may also include heterocyclic nitrogen compounds known in the art, some of which are described herein.

[0136] Still other development methodologies may include the use of a deprotection solvent. Non-limiting deprotection solvents include organic acids (e.g., any of those herein such as oxalic acid), or choline hydroxides ([N(CH 3 ) 3 CH 2 CH 2 OH] + [OH] - ) such as choline ([N(CH 3 ) 3 CH 2 CH 2 OH] + ).

[0137] The developer can be used at any useful concentration. In one embodiment, the developer solution contains from about 0.5 wt% to about 30 wt% of the developer in a solvent (e.g., an aqueous solvent, a non-aqueous solvent, an organic solvent, or a combination thereof) (including concentrations from about 1 wt% to about 20 wt% and from 1.1 wt% to 10 wt%).

[0138] The developer can be used with one or more additives such as oxidizing agents, surfactants, salts, and chelating agents. The additives can optionally be present in the developer solution in an amount of less than 10 wt% or less than 5 wt%. Non-limiting oxidizing agents include peroxides or peracids such as hydrogen peroxide, benzoyl peroxide, urea peroxide, or mixtures thereof. Non-limiting surfactants include anionic, cationic, and non-ionic surfactants, such as alkylphenol ethoxylates (e.g., Triton™ X-100 (polyethylene glycol tert-octylphenyl ether), octylphenol ethoxylate, or nonylphenol ethoxylate), alcohol ethoxylates (e.g., BRIJ® 56 (C 16 H 33 (OCH 2 CH 2 ) 10 OH), BRIJ® 58 (C 16 H 33 (OCH 2 CH 2 ) 20 OH), or aliphatic alcohol ethoxylates), fatty acid ethoxylates, poloxamers, fatty acid esters of glycerol, acetylenediols, amine ethoxylates, glucosides, glucamides, polyethylene glycol, or poly(ethylene glycol-co-propylene glycol), perfluoroalkylammonium (e.g., perfluoroalkylsulfonic acid ammonium or carboxylic acid ammonium), and combinations thereof.

[0139] Non-limiting salts include cations selected from the group consisting of ammonium, d-block metal cations (such as hafnium, zirconium, lanthanum, etc.), f-block metal cations (such as cerium, lutetium, etc.), p-block metal cations (such as aluminum, tin, etc.), alkali metals (such as lithium, sodium, potassium, etc.), and combinations thereof, and anions selected from the group consisting of fluoride, chloride, bromide, iodide, nitrate, sulfate, phosphate, silicate, borate, peroxide, butoxide, formate, oxalate, ethylenediaminetetraacetic acid (EDTA), tungstate, molybdate, etc., and combinations thereof. Non-limiting chelating agents can include polyamines, alcoholamines, amino acids, carboxylic acids, or combinations thereof.

[0140] In certain embodiments, the positive developer is an acidic developer in an aqueous solvent, an acidic developer in an organic solvent, an aqueous alkaline developer (e.g., containing NH 2 O 2 OH, TMAH, TEAH, TPAH, or TBAH regardless of the presence or absence of H 4 ), an aqueous acidic developer (e.g., containing HCl or HF), an organic developer, or a deprotection solvent (e.g., containing oxalic acid, choline, or choline hydroxide). The developer can include one solvent or a combination of solvents.

[0141] As described herein, a dry development process can be used to treat the film (e.g., dry development can be used alone, before wet development, or after wet development). Non-limiting processes can include the use of halides such as HCl-based or HBr-based processes. Although the present disclosure is not limited to a particular theory of operation or mechanism, the approach involves a dry-deposited EUV photoresist film and a clean chemical (e.g., HCl, HBr, and BCl 3) is understood to utilize the chemical reactivity and form volatile products using vapor or plasma. Such volatile products can be removed in any manner (e.g., by treatment with an aqueous acid solution as described herein). Dry deposited EUV photoresist films can be removed at an etching rate of up to 1 nm / second. The rapid removal of dry deposited EUV photoresist films by these chemicals is applicable to chamber cleaning, backside cleaning, bevel cleaning, and PR development. The film can be removed using vapor at various temperatures (e.g., HCl or HBr at temperatures above -10°C, or BCl 3 ) but it is also possible to use plasma to further accelerate or enhance the reactivity.

[0142] Plasma processes include transformer coupled plasma (TCP), inductively coupled plasma (ICP), or capacitively coupled plasma (CCP) using equipment and techniques known in the art. For example, the process can be carried out at a pressure of >0.5 mTorr (e.g., 1 mTorr to 100 mTorr, etc.) and at a power level of <1000 W (e.g., <500 W). The temperature can be between 30°C and 300°C (e.g., 30°C to 120°C) for 1 to 3000 seconds (e.g., 10 seconds to 600 seconds), and the flow rate can be 100 to 1000 standard cubic centimeters per minute (sccm), e.g., about 500 sccm.

[0143] When the flow of the halide reactant is hydrogen gas and a halide gas, remote plasma / UV radiation is used to form H 2 and Cl 2 and / or Br 2Generate radicals, flow hydrogen and halide radicals into the reaction chamber, and contact them with the patterned EUV photoresist on the substrate layer of the wafer. Appropriate plasma power can range from 100 W to 500 W without bias. These conditions are suitable for some processing reactors, such as the Kiyo etching tool available from Lam Research in Fremont, California, but it should be understood that a wider range of process conditions can be used depending on the capabilities of the processing reactor.

[0144] In the thermal development process, the substrate is exposed to a dry development chemical (such as a Lewis acid) in a vacuum chamber (such as an oven). Suitable chambers can include a vacuum line, a dry development hydrogen halide chemical gas (such as HBr, HCl) line, and a heater for temperature control. In some embodiments, the interior of the chamber can be coated with a corrosion-resistant film such as an organic polymer or an inorganic coating. One such coating is polytetrafluoroethylene ((PTFE), such as Teflon (trademark)). Such materials can be used in the thermal processes of the present disclosure without the risk of removal by plasma exposure.

[0145] The process conditions for dry development can be, depending on the photoresist films and their composition and properties, about 10 seconds to 1 minute without plasma, a reactant flow rate of 100 sccm to 500 sccm (such as 500 sccm of HBr or HCl), a temperature of -10°C to 120°C (such as -10°C), and a pressure of 1 mTorr to 500 mTorr (such as 300 mTorr).

[0146] In various embodiments, the method of the present disclosure combines all dry steps of film deposition, formation by vapor deposition, and (EUV) lithography photopatterning, followed by wet development with an aqueous acid solution. In other embodiments, the method of the present disclosure combines all dry steps of film deposition, formation by vapor deposition, (EUV) lithography photopatterning, and dry development, followed by wet treatment with an aqueous acid solution. In such a process, the substrate can proceed directly to a dry development / etching chamber following photopatterning in an EUV scanner.

[0147] Other processes The method can include any other useful processes, as described below.

[0148] In the backside and bevel cleaning process, it is possible to confine the vapor and / or plasma to specific regions of the wafer and reliably remove only the backside and bevels without degrading the film on the surface of the wafer. The dry-deposited EUV photoresist film to be removed is generally composed of Sn, O, and C, but the same cleaning approach can be extended to films of other metal oxide resists and materials. In addition, this approach can also be used for film stripping and photoresist rework.

[0149] Suitable process conditions for dry bevel edge and backside cleaning are a reactant flow rate of 100 sccm to 500 sccm (e.g., 500 sccm of HCl, HBr, or H 2 and Cl 2 or Br 2 、BCl 3 or H 2) can be at a temperature of -10°C to 120°C (e.g., 20°C), a pressure of 20 mTorr to 500 mTorr (e.g., 300 mTorr), and a plasma power of 0 to 500 W at a high frequency (e.g., 13.56 MHz). These conditions are suitable for some processing reactors, such as the Kiyo etching tool available from Lam Research in Fremont, California, but it should be understood that a wider range of process conditions can be used depending on the capabilities of the processing reactor.

[0150] The photolithography process can involve one or more bake steps to facilitate the chemical reactions necessary to create a chemical contrast between the exposed and unexposed areas of the photoresist. In high volume manufacturing (HVM), such bake steps can be performed on a track where the wafer is baked on a hot plate at a preset temperature under ambient air or, in some cases, N 2 flow. More careful control of the bake atmosphere during these bake steps, as well as the introduction of additional reactive gas components into the atmosphere, can help further reduce the dose requirements and / or improve pattern fidelity.

[0151] According to various aspects of the present disclosure, one or more post-treatments on metal and / or metal oxide-based photoresists after deposition (e.g., post-application bake (PAB) or another post-application process) and / or exposure (e.g., post-exposure bake (PEB) which can be omitted, or another post-exposure process) and / or development (e.g., post-development bake (PDB) or another post-development process) can increase the difference in material properties between the exposed photoresist and the unexposed photoresist, thus reducing the dose-to-size (DtS), improving the PR profile, and improving the line edge roughness and line width roughness (LER / LWR) after subsequent dry development. Such processes can involve thermal processes that control temperature, gas atmosphere, and moisture, resulting in improved dry development performance in subsequent processes. In some cases, remote plasma may be used. Further, in certain cases, PAB and / or PEB and / or PDB are not performed.

[0152] In the case of a post-application process (e.g., PAB), temperature (e.g., involving heating or cooling), gas atmosphere (e.g., air, H 2 O, CO 2 , CO, O 2 , O 3 , CH 4 , CH 3 OH, N 2 , H 2 , NH 3 , N 2 O, NO, Ar, He, or a mixture thereof) or under vacuum, and a thermal process that controls moisture can be used after deposition and before exposure to change the composition of the unexposed metal and / or metal oxide photoresist. This change can increase the EUV sensitivity of the material, thus achieving a reduction in dose-to-size and edge roughness after exposure and dry development.

[0153] In the case of a post-exposure process (e.g., PEB), temperature, gas atmosphere (e.g., air, H 2 O, CO 2 , CO, O 2 , O 3 , CH4 、 CH 3 OH, N 2 、 H 2 、 NH 3 、 N 2 O, NO, Ar, He, or a mixture thereof) or under vacuum, and using a thermal process to control moisture, the composition of both the unexposed photoresist and the exposed photoresist can be changed. This change can increase the difference in composition / material properties between the unexposed photoresist and the exposed photoresist, and the difference in etching rate of the dry development etching gas between the unexposed photoresist and the exposed photoresist. Thereby, a higher etching selectivity can be achieved. The improved selectivity can obtain a more square PR profile with improved surface roughness and / or less photoresist residue / scum. In certain embodiments, the PEB can be carried out in air, in the optional presence of moisture and CO 2 . In other embodiments, the PEB can be omitted.

[0154] In the case of post-development processing (e.g., post-development bake or PDB), temperature, gas atmosphere (e.g., air, H 2 O, CO 2 , CO, O 2 , O 3 , CH 4 , CH 3 OH, N 2 , H 2 , NH 3 , N 2 O, NO, Ar, He, or a mixture thereof) or under vacuum (e.g., using UV), and using a thermal process to control moisture, the composition of the unexposed photoresist can be changed. In certain embodiments, the conditions also include the use of plasma (e.g., O 2 , O 3 , Ar, He, or a mixture thereof). This change can increase the hardness of the material, which can be beneficial when the film is used as a resist mask when etching the underlying substrate.

[0155] In these cases, in an alternative embodiment, the thermal process can be replaced with a remote plasma process to increase the reactive species, lower the energy barrier to the reaction, and increase productivity. The remote plasma can generate more reactive radicals and thus lower the reaction temperature / time for the process, leading to an increase in productivity.

[0156] Accordingly, one or more processes can be applied to modify the photoresist itself to increase the selectivity of wet or dry development. This thermal or radical modification can increase the contrast between the unexposed and exposed materials and thus increase the selectivity of the subsequent development step. The resulting difference in the material properties between the unexposed and exposed materials can be adjusted by adjusting process conditions including temperature, gas flow, moisture, pressure, and / or RF power.

[0157] For wet or dry development resist films, the processing temperature in PAB, PEB, or PDB can be varied over a range of, for example, about 90 °C to 250 °C for PAB and about 170 °C to 250 °C or higher for PEB and / or PDB to adjust and optimize the processing. In certain embodiments, PEB is omitted.

[0158] In certain embodiments, the PAB, PEB, and / or PDB processes can be performed at a pressure between atmospheric and vacuum, in a gas ambient flow in the range of 100 sccm to 10,000 sccm, with a water content in the amount of a few percent to up to 100% (e.g., 20% to 50%), for a period of about 30 seconds to 15 minutes, e.g., about 1 to 2 minutes. In certain embodiments, PEB is omitted.

[0159] Depending on the selectivity requirements / constraints of the semiconductor processing operation, the necessary EUV dose can be reduced using heat treatment as described herein. Or, if higher selectivity is required and a higher dose is acceptable, much higher selectivity (up to 100 times the exposed to unexposed) can be obtained.

[0160] Still other steps can include in-situ measurements capable of evaluating physical and structural characteristics (e.g., critical dimensions, film thickness, etc.) during the photolithography process. Modules for performing in-situ measurements can include, for example, a scatterometry module, a polarization analysis module, a downstream mass spectrometry module, and / or a plasma-enhanced downstream emission spectroscopy module.

[0161] Returning to FIG. 2, in block 220 of process 200, a substrate is provided within the process chamber, and the substrate is a semiconductor substrate comprising a substrate layer and a developed photoresist mask on the substrate layer. The substrate layer may be beneath the developed photoresist mask and may include any suitable material to facilitate the patterning process. The substrate layer can be etched with high selectivity with respect to the developed photoresist mask. In some embodiments, the substrate layer is spin-on carbon (SoC), spin-on glass (SOG), amorphous carbon (a-C), tin oxide (e.g., SnO x ), silicon (e.g., a-Si), silicon oxide (e.g., SiO x ), silicon oxynitride (e.g., SiO x N y ), silicon oxycarbide (e.g., SiO x C y ), silicon nitride (Si 3 N 4 ), silicon carbide (SiC x ), titanium oxide (e.g., TiO 2 ), titanium nitride (e.g., TiN), tungsten (e.g., W), doped carbon (e.g., W-doped C), tungsten oxide (e.g., WO x ), hafnium oxide (HfO 2 ), zirconium oxide (e.g., ZrO 2 ), or aluminum oxide (Al 2 O 3 ).

[0162] The metal-containing photoresist can be deposited dry or wet on a substrate layer. The metal-containing photoresist may be provided as a positive or negative resist having EUV-exposed regions and EUV-unexposed regions after EUV exposure. After deposition, the metal-containing photoresist can be photopatterned within an EUV lithography chamber (scanner). After exposure and optional PEB treatment, the metal-containing photoresist can be developed to selectively remove a portion of the metal-containing photoresist (e.g., the EUV-unexposed portion) to form a patterned photoresist mask on the substrate layer. In some embodiments, the metal-containing photoresist is a metal-containing EUV photoresist, and the metal-containing EUV photoresist is an organometallic oxide or an organometallic-containing film. For example, the metal-containing EUV photoresist can include Sn, O, and C atoms.

[0163] The process chamber can provide a sealed space for processing the substrate after development. The chamber walls within the process chamber can be fabricated from stainless steel, aluminum, plastic, or other suitable materials. In some embodiments, the chamber walls are coated with a corrosion-resistant film such as a polymer or inorganic coating. The process chamber may include a substrate support (e.g., pedestal or electrostatic chuck) on which the substrate is supported. In some embodiments, the process chamber for post-development processing may be a deposition chamber, a bevel edge and / or backside cleaning chamber, a PAB processing chamber, a PEB processing chamber, a development chamber, or an etching chamber. In this way, the process chamber for post-development processing may be the same chamber used in a previous operation for photoresist processing or the same chamber used in a subsequent operation for photoresist processing, thereby minimizing the transfer of the substrate and reducing exposure to the air break between operations. The process chamber may include one or more heating elements for exposing the substrate to a high temperature. In some embodiments, the one or more heating elements may include one or more infrared (IR) lamps or one or more light-emitting diodes (LEDs) located on the substrate support to control the temperature of the substrate. The process chamber may include one or more gas lines for feeding gas into the process chamber. For example, the one or more gas lines may include a showerhead for supplying a reactive gas towards the substrate within the process chamber. In some embodiments, the process chamber may be a plasma generation chamber or may be coupled to a plasma generation chamber separate from the process chamber. The plasma generation chamber may be an inductively coupled plasma (ICP) reactor, a capacitively coupled plasma (CCP) reactor, or a capacitively coupled plasma (CCP) reactor. Optionally, the process chamber further includes one or more gas outlets for discharging gas, and the gas outlets may or may not be coupled to a vacuum pump to maintain a desired pressure within the process chamber.

[0164] In block 230 of process 200, the developed metal-containing photoresist mask is processed using one or more of the following operations: (i) thermally annealing the developed metal-containing photoresist mask, (ii) exposing the developed metal-containing photoresist mask to plasma, (iii) exposing the developed metal-containing photoresist mask to one or more reactive gases, and (iv) selectively depositing a protective layer on the developed metal-containing photoresist mask. The post-development processing of the substrate can utilize one of the aforementioned thermal annealing, plasma, chemical, or selective deposition processing operations, or a combination of the aforementioned processes. The post-development processing improves the performance of the metal-containing photoresist mask during pattern transfer etching. The aforementioned thermal annealing, plasma, chemical, and selective deposition processing techniques are described in detail below.

[0165] In block 240 of process 200, the substrate layer is etched to form recessed features using the developed metal-containing photoresist mask. This process is sometimes referred to as pattern transfer or pattern transfer etching. The etching can selectively remove a portion of the substrate layer without removing the developed metal-containing photoresist mask. It is possible to etch the portion of the substrate layer exposed by the developed metal-containing photoresist mask using a wet or dry etchant. The metal-containing photoresist mask can define the pattern in which the features are etched. The features are etched through the substrate layer according to the pattern defined by the metal-containing photoresist mask. After the post-development processing, the metal-containing photoresist mask may be capable of increasing the line CD and / or improving the etching resistance during pattern transfer etching. The features being etched can maintain or substantially maintain the line CD provided by the metal-containing photoresist mask. In some cases, the defect rate and / or roughness of the metal-containing photoresist mask can be reduced. As a result, the defects and roughness are not transferred to the features formed after pattern transfer etching.

[0166] Heat treatment In some embodiments, the substrate can be heat treated by heating the substrate to a high temperature. Heat treatment of the substrate can serve to reduce defects and reduce roughness from the metal-containing photoresist mask prior to pattern transfer etching. In particular, heat treatment of the substrate can improve the chemical contrast in the metal-containing photoresist mask by removing scum.

[0167] After wet or dry development, residues or scum may remain on the substrate. Residues or scum may remain in the areas of the photoresist mask that have been removed by development. Residues or scum may include residual etching by-products adsorbed on the surface of the substrate. For example, the vapor of a halogen used in a particular developing chemical can react with moisture or oxygen to form residual etching by-products that are difficult to remove. Wet processing techniques often use moisture and / or oxygen, which are more likely to cause the formation of scum and residues. In some cases, the residues can contribute to a loss of chemical contrast during pattern transfer and can contaminate downstream processing tools, high-concentration metals or metal oxides (e.g., SnO x ) may contain particles or clusters.

[0168] After wet or dry development, roughness may form on the sidewalls of the etched features in the developed pattern of the photoresist mask. This is thought to be due to the probability theory of light or non-optimal Gaussian distribution of light where part of the material is partially or completely exposed in an area where the photoresist should remain unexposed, or vice versa. Additionally, scum on the sidewalls of the etched features of the photoresist mask can exacerbate the roughness.

[0169] During heat treatment, the substrate may be heated to a high temperature of about 50°C to about 500°C, about 100°C to about 400°C, about 100°C to about 300°C, or about 100°C to about 250°C. The substrate can be heated to a high temperature using one or more temperature-controllable elements within the process chamber. The pressure can be maintained at about 0.1 Torr to about 760 Torr, for example, in some cases about 0.1 Torr to about 1 Torr. The substrate may be exposed to a high temperature for a period of about 1 minute to about 10 minutes, for example, in some cases about 2 minutes to about 5 minutes. In some embodiments, the heat treatment is carried out using one or more inert gases. For example, the heat treatment can be carried out using a flow of nitrogen (N 2 ), helium (He), neon (Ne), argon (Ar), or xenon (Xe). In some embodiments, the heat treatment is carried out in air.

[0170] When the temperature of the post-development heat treatment is high, the descum may increase, the defect rate may be reduced, and the roughness may be reduced. However, when the temperature increases, the line CD may decrease at the same time. It has been observed that when the temperature during thermal annealing increases, lateral shrinkage of the photoresist and shrinkage of the height of the photoresist occur. Due to the decrease in line CD, the dose-to-size becomes higher. In post-development heat treatment, when the dose-to-size becomes higher, a trade-off between the reduction of the defect rate and the roughness may occur. As a result, the heat treatment is limited to a desired temperature range and a desired treatment period, and the advantages of reducing defects and roughness are optimized while minimizing the increase in dose-to-size.

[0171] Plasma treatment In some embodiments, the substrate may be exposed to plasma for post-development processing. The plasma treatment can serve to densify the metal-containing photoresist mask and reduce roughness prior to pattern transfer etching. In some cases, the plasma treatment can further improve the chemical contrast in the metal-containing photoresist mask by removing scum. The plasma treatment can use a plasma of inert gas species or a plasma of reactive gas species. The plasma of reactive gas species can chemically react with the metal-containing photoresist mask or selectively deposit a protective film on the metal-containing photoresist mask.

[0172] Exposure to plasma can be facilitated by generating plasma in a remote plasma generator or in the process chamber where the substrate is processed. One or more gases may be flowed into the plasma generation region, which can be a remote plasma generator or a process chamber, and the plasma is ignited. The plasma generation chamber may be an inductively coupled plasma (ICP), capacitively coupled plasma (CCP), or transformer coupled plasma (TCP) reactor. Plasma energy is provided to activate one or more gases into ions, radicals, neutral species, and other plasma-activated species. The ions, radicals, neutral species, and other plasma-activated species can interact with the metal-containing photoresist mask and improve the performance of the metal-containing photoresist mask during pattern transfer etching.

[0173] One or more gases can include oxygen-containing species such as oxygen (O 2 ), carbon dioxide (CO 2 ), and carbon monoxide (CO). Additionally or alternatively, one or more gases can include boron trichloride (BCl 3 ), silicon tetrachloride (SiCl 4 ), tin tetrachloride (SnCl 4 ), tungsten hexafluoride (WF 6 ), and difluoromethane (CH 2 F 2It may contain halogen-containing species such as. Additionally or alternatively, one or more gases may contain inert gas species such as nitrogen (N 2 ), helium (He), neon (Ne), argon (Ar), and xenon (Xe). Other gases may contain hydrogen (H 2 ), ammonia (NH 3 ), hydrogen halides (HCl, HBr, HF, HI), and various hydrocarbons (C 4 ) such as methane (CH x H y ). In some cases, the plasma may be an oxygen-based plasma, a nitrogen-based plasma, an inert gas plasma, and / or a carbon-based plasma. In some embodiments, the plasma is a remote plasma. In some other embodiments, the plasma is an in-situ plasma.

[0174] It is possible to adjust the process conditions for plasma treatment to achieve the desired results. Such process conditions include, but are not limited to, plasma power, plasma frequency, plasma exposure time, bias voltage, duty cycle, temperature (e.g., pedestal temperature), pressure (e.g., chamber pressure), and the flow rate of one or more gases. The plasma during operation can be generated at a plasma power of less than about 6 kW, such as about 50 W to about 4000 W, about 50 W to about 1000 W, or about 100 W to about 500 W. In some cases, the plasma may be supplied with low plasma output and high ion energy. The directionality of the plasma can be controlled by the bias voltage. In some embodiments, a bias voltage of about 1 V to about 500 V, about 10 V to about 400 V, or about 30 V to about 300 V can be applied. The plasma treatment can be applied over a period of about 0.5 seconds to about 120 seconds, about 1 second to about 60 seconds, or about 2 seconds to about 40 seconds. The plasma treatment may adjust the duty cycle of the plasma during operation to achieve the desired result, and the RF power supply can deliver the plasma at any suitable duty cycle, such as about 1% to about 99%, or about 10% to about 90%. In some embodiments, the chamber pressure may be about 0.1 Torr to about 760 Torr, or in some cases about 0.1 Torr to about 1 Torr. In some embodiments, the substrate temperature may be about 0 °C to about 400 °C, about 50 °C to about 300 °C, or about 100 °C to about 250 °C.

[0175] As described below, plasma treatment may involve reactive gas species. The plasma of reactive gas species can induce a chemical reaction in the metal-containing photoresist mask and improve mask properties such as etching resistance. The plasma of reactive gas species can increase the line CD and decrease the dose-to-size by selectively depositing a protective film on the metal-containing photoresist mask.

[0176] Chemical treatment In some embodiments, the metal-containing photoresist mask may be exposed to one or more reactive gas species. The reactive gas species may be capable of chemically reacting with the metal-containing photoresist mask. In fact, certain reactive gas species may react with the metal-containing photoresist mask but not with the substrate layer of the substrate. In some embodiments, the reactive gas species may be able to convert all or substantially all of the metal-containing photoresist mask from a first material to a second material. The change in the chemistry of the metal-containing photoresist mask may cause one or more properties of the metal-containing photoresist mask to change. In some embodiments, the reactive gas species may convert only the outer portion of the metal-containing photoresist mask from a first material to a second material, which can be used as a protective film as further described below.

[0177] The reactive gas species can react with the metal-containing photoresist mask to increase the line CD and decrease the dose-to-size. The reactive gas species can react with the metal-containing photoresist mask to reduce the roughness (e.g., LWR / LER) or at least maintain the same roughness. The reactive gas species can densify the metal-containing photoresist mask. In some cases, the reactive gas species may react with the metal-containing photoresist mask to reduce the defect rate (e.g., scum). Additionally, the reactive gas species can reduce gas evolution such as the gas evolution of tin from the metal-containing photoresist mask. In some cases, the reactive gas species may react with the metal-containing photoresist mask and increase the etching resistance of the photoresist mask during a subsequent etching operation. As an example, the reactive gas species can increase the line CD of the photoresist mask after pattern transfer etching and can maintain the increased line CD at least substantially.

[0178] The reactive gas species may have a higher reactivity with the metal-containing photoresist compared to the underlying substrate layer. In certain embodiments, the chemical treatment using the reactive gas species exploits the chemical properties of the EUV photoresist mask. The EUV photoresist mask can be composed of an organometallic oxide film such as an organotin oxide film having Sn, O, and C atoms. The organotin oxide film can be composed of a network of Sn-Sn bonds, Sn-H bonds, Sn-C bonds, Sn-OH bonds, Sn-O bonds, Sn-O-Sn bonds, and Sn-O-C bonds. The reactive gas species can react with one or more elements of the organotin oxide film by oxidation, reduction, insertion, extraction, or other chemical reaction mechanisms to induce a chemical change in the EUV photoresist mask. In some cases, the reactive gas species can include carbon monoxide (CO), and the tin species can have a catalytic reaction with carbon monoxide. Without being limited by any theory, the compound SnOCx reacts with CO to form a new compound SnOCx(CO)y. The chemical reaction induces a change in the EUV photoresist mask by expanding the line CD. In some embodiments, the etching resistance of the new compound in the EUV photoresist mask is improved.

[0179] Chemical reactions can be induced in the EUV photoresist mask using reactive gas species other than CO. Examples of useful reactive gas species include, but are not limited to, air, water vapor (H 2 O), hydrogen peroxide (H 2 O 2 ), carbon dioxide (CO 2 ), oxygen (O 2 ), ozone (O 3 ), methane (CH 4 ), methanol (CH 3 OH), ethanol (CH 3 CH 2 OH), nitrogen (N 2 ), hydrogen (H 2 ), ammonia (NH 3 ), nitrous oxide (N 2 O), nitric oxide (NO), nitrogen dioxide (NO 2 ), acetylacetone (C 5 H8 O 2 )), formic acid (CH 2 O 2 ), acetic acid (CH 3 COOH), hydrogen cyanide (HCN), boron trichloride (BCl 3 ), silicon tetrachloride (SiCl 4 ), chlorine (Cl 2 ), bromine (Br 2 ), hydrogen chloride (HCl), hydrogen bromide (HBr), hydrogen iodide (HI), hydrogen fluoride (HF), fluoromethane (CH 3 F), difluoromethane (CH 2 F 2 ), and combinations thereof may be included. In some cases, the reactive gas species may include an oxygen-containing gas, a carbon-containing gas, a hydrogen-containing gas, a nitrogen-containing gas, a halogen-containing gas, or a combination thereof. Other reactive gas species may include metal precursors such as tungsten hexafluoride (WF 6 ), tin tetrachloride (SnCl 4 ), molybdenum hexafluoride (MoF 6 ), molybdenum dichloride dioxide (MoO 2 Cl 2 ), and molybdenum chloride (MoCl 5 ). Other reactive gas species may include metal organic precursors such as tin tetrakis(dimethylamide) (Sn(N(CH 3 )) 2 ), hafnium tetrakis(dimethylamide) (Hf(N(CH 4 )) 3 ), dimethylaluminum ((CH 2 )) 4 Al), trimethylaluminum ((CH 3 )) 2 Al), titanium isopropoxide (Ti(OCH(CH 3 )) 3 ), tungsten carbonyl (W(CO 3 )) 2 ), molybdenum carbonyl (Mo(CO) 4 ), ruthenium carbonyl (Ru(CO) x ), iron carbonyl (Fe(CO) x ), ruthenium carbonyl (Ru(CO) x ), iron carbonyl (Fe(CO)x ) and combinations thereof may be included. Thus, in some cases, the reactive gas species may include organometallic precursors such as metal halides or metal carbonyl precursors. Conventional polymer-based photoresist materials may not react with metal halides or certain organometallic precursors, but the metal-containing or metal oxide-containing photoresist materials of the present disclosure may be likely to react with metal halides and organometallic precursors. Without being limited by any theory, when an M-OH bond is present in an organometallic photoresist, an M-O-M’ bridge may be formed, where M’ is derived from a metal precursor (e.g., a metal halide or an organometallic precursor).

[0180] The reactive gas species may be co-flowed with other gases. In some embodiments, the reactive gas species may be co-flowed with an inert gas species such as helium, neon, argon, or xenon. In some embodiments, combinations of reactive gas species may be co-flowed with each other. By way of example, a halogen-containing gas such as boron trichloride may be co-flowed with a carbon-containing gas such as methane. In another example, a metal precursor such as tungsten hexafluoride may be co-flowed with a carbon-containing gas such as difluoromethane. The reactive gas species, alone or in combination with other reactive gas species, can convert a photoresist mask to another material or selectively deposit a protective film on the photoresist mask.

[0181] In some embodiments, the reactive gas species can be supplied to the process chamber from a gas source fluidly coupled to the process chamber. A gas source, such as a gas storage tank, can be fluidly coupled to the process chamber via a gas supply line. The gas reactants may be premixed before entering the process chamber or may be mixed when entering the process chamber. In some embodiments, the reactive gas species can be generated in-situ within the process chamber. The gas reactants can react with each other and with the metal-containing photoresist mask to form reaction products that induce chemical changes. Or the gas reactants can react with one or more chamber components (e.g., metal-based chamber lines) and with the metal-containing photoresist mask to form reaction products that induce chemical changes. The gas reactants may be carbon-containing precursors that react with the metal chamber components to form organometallic precursors. This reaction can be thermally driven to produce organometallic precursors. For example, carbon monoxide supplied to the process chamber reacts with an iron-containing chamber line to form iron carbonyl (Fe(CO) x ) that readily reacts with the EUV photoresist mask, thereby increasing the line CD of the EUV photoresist mask. Without being limited by any theory, iron carbonyl causes the deposition of iron oxide on the EUV photoresist mask. In another example, carbon monoxide or carbon dioxide supplied to the process chamber can react with a tungsten-containing chamber line (e.g., a hot wire) to form tungsten carbonyl (W(CO) x ) that readily reacts with the EUV photoresist mask.

[0182] The chemical treatment of a metal-containing photoresist mask with one or more reactive gases can be used in conjunction with one or both of heat treatment and plasma treatment. A trade-off may occur with heat treatment or plasma treatment alone, but such a trade-off can be offset by further applying chemical treatment to the metal-containing photoresist mask. Specifically, the chemical treatment can be combined with heat treatment such that one or more reactive gas species are flowed over the metal-containing photoresist mask at an elevated temperature. Although the line CD may decrease as the temperature increases, one or more reactive gas species may increase the line CD in the metal-containing photoresist mask. In fact, the increase in line CD due to one or more reactive gas species may exceed the decrease in line CD due to the increase in temperature. Thereby, the dose-to-size is reduced while reducing the defect rate and roughness in the metal-containing photoresist mask. In some embodiments, the chemical treatment can be combined with plasma treatment such that radicals and / or ions of the reactive gas species are flowed over the metal-containing photoresist mask. The radicals and / or ions can increase the reactivity between the reactive gas species and the metal-containing photoresist mask. The metal-containing photoresist mask may be exposed to one or more reactive gas species in the plasma, which may change the chemical composition of the metal-containing photoresist mask and increase the line CD and density. This can be done without necessarily degrading the defect rate or roughness of the metal-containing photoresist mask. The plasma can be applied at a power such that damage to the substrate is avoided.

[0183] Induction of surface or bulk reactions in a metal-containing photoresist mask can occur by applying energy to the reaction. A certain amount of energy by thermal exposure and / or plasma exposure may be sufficient to induce surface or bulk reactions. Therefore, it is possible to adjust process conditions such as temperature and plasma power to achieve the desired results. In some embodiments, the substrate temperature during chemical treatment using one or more reactive gas species may be from about 0 °C to about 400 °C, from about 50 °C to about 300 °C, or from about 100 °C to about 250 °C. In some embodiments, the plasma power during chemical treatment using one or more reactive gas species may be less than about 6 kW, from about 50 W to about 4000 W, from about 50 W to about 1000 W, or from about 100 W to about 500 W.

[0184] Other process conditions such as plasma frequency, exposure time, bias voltage, pressure, and flow rate can be adjusted to facilitate a chemical treatment using one or more reactive gas species. In some embodiments, a bias voltage of less than about 800 V, about 0 V to about 500 V, about 10 V to about 400 V, or about 30 V to about 300 V can be applied. In some embodiments, exposure to one or more reactive gas species can be applied over a period of about 1 second to about 10 minutes, about 5 seconds to about 8 minutes, or about 30 seconds to about 4 minutes. In some embodiments, the chamber pressure can be about 0.1 Torr to about 760 Torr, or in some cases about 1 mTorr to about 100 mTorr. The first reactive gas species can be flowed into the process chamber at a flow rate of about 1 sccm to about 1000 sccm, about 2 sccm to about 500 sccm, or about 5 sccm to about 300 sccm. An optional second reactive gas species can be flowed in parallel in the process chamber at a flow rate of about 5 sccm to about 1000 sccm, about 10 sccm to about 500 sccm, or about 20 sccm to about 300 sccm. An optional inert gas species can be flowed in parallel in the process chamber at a flow rate of about 20 sccm to about 2000 sccm, about 30 sccm to about 1000 sccm, or about 50 sccm to about 500 sccm. As an example, carbon monoxide can be flowed into the process chamber at a flow rate of about 500 sccm at a substrate temperature of about 240 °C over a period of about 20 seconds to about 5 minutes. Carbon monoxide can react with the EUV photoresist mask and potentially change the chemical composition of the EUV photoresist mask. In an alternative example, tungsten hexafluoride can react with the EUV photoresist mask instead of carbon monoxide and change the chemical composition of the photoresist mask. The EUV photoresist mask may exhibit increased etch resistance during subsequent pattern transfer etching.

[0185] Figures 3A - 3D show cross - sectional schematic views of various processing stages including the development and processing of a photoresist, and one or more properties of the photoresist change due to the processing. As shown in Figure 3A, wafer 300 includes a substrate 302 and a substrate layer 304 to be etched. In some embodiments, substrate layer 304 includes an amorphous carbon, spin - on carbon, or other materials, such as an ashing - capable hard mask of silicon, silicon oxide, silicon nitride, silicon carbide, etc. In some embodiments, substrate layer 304 may be a layer stack disposed on substrate 302. Wafer 300 further includes a photo - patterned metal - containing EUV resist film 306. For example, the photo - patterned metal - containing EUV resist film 306 may be an organometal - containing layer disposed on the substrate layer 304 to be etched. The photo - patterned metal - containing EUV resist film 306 may have a thickness of about 5 nm to about 50 nm, or about 10 nm to about 30 nm. The photo - patterned metal - containing EUV resist film 306 may be provided in a process chamber after photopatterning with an EUV scanner and / or after PEB treatment. The photo - patterned metal - containing EUV resist film 306 includes a non - EUV exposure region 306a and an EUV exposure region 306b.

[0186] As shown in Figure 3B, the non - EUV exposure region 306a of the photo - patterned metal - containing EUV resist film 306 is removed in the development process. For development, a wet development chemical or a dry development chemical can be used. When a dry development chemical is applied, the dry development can proceed with or without applying plasma. In some embodiments, the dry development chemical may include a halide - containing chemical. The photoresist mask of the photo - patterned metal - containing EUV resist film 306 is formed by removing the non - EUV exposure region 306a after development. Although Figures 3A - 3D illustrate negative development, it will be understood that positive development can be applied instead in the present disclosure.

[0187] As shown in FIG. 3C, the developed photoresist mask can be subjected to a process of changing one or more material properties to produce a chemically modified photoresist mask 308. The chemically modified photoresist mask 308 may have a chemical composition different from that of the photopatterned metal-containing EUV resist film 306. Different from conventional polymer-based photoresist masks, the photopatterned metal-containing EUV resist film 306 may be composed of metal oxides. The photopatterned metal-containing EUV resist film 306 may be composed of a network of Sn-Sn bonds, Sn-H bonds, Sn-C bonds, Sn-OH bonds, Sn-O bonds, Sn-O-Sn bonds, and Sn-O-C bonds. Organic gas species, organometallic gas species, metal-containing gas species, and other reactive gas species can react with the photopatterned metal-containing EUV resist film 306. Many of the aforementioned gas species would not normally react with conventional polymer-based photoresist masks. The reactive gas species of the present disclosure utilize the chemical properties of the photopatterned metal-containing EUV resist film 306 to produce a chemically modified photoresist mask 308.

[0188] The reaction with the photopatterned metal-containing EUV resist film 306 is a diffusion-controlled reaction. Therefore, only a part of the photopatterned metal-containing EUV resist film 306 is converted to a new composition, or the entire photopatterned metal-containing EUV resist film 306 is converted to a new composition. The diffusion-controlled reaction can be controlled by parameters such as process time, pressure, and temperature. By way of example, the longer the exposure time, the deeper the diffusion obtained. In addition, the higher the temperature, the more likely it is to contribute to an increase in diffusion and reactivity. By adjusting some of the aforementioned parameters, part or all of the photopatterned metal-containing EUV resist film 306 is converted to a chemically modified photoresist mask 308.

[0189] In some embodiments, the reactive gas species react with the metal-containing EUV resist film 306 that has been photopatterned at high temperature, whereby the reaction is thermally driven. Thus, the chemically modified photoresist mask 308 can be produced under heat treatment and chemical treatment. In some embodiments, the reactive gas species react with the metal-containing EUV resist film 306 that has been photopatterned under plasma exposure, in-situ plasma exposure, or remote plasma exposure. The radicals and / or ions of the reactive gas species can react more readily with the photopatterned metal-containing EUV resist film 306. Thus, the chemically modified photoresist mask 308 can be produced under plasma treatment and chemical treatment.

[0190] The chemically modified photoresist mask 308 can have one or more new material properties. In some embodiments, the chemically modified photoresist mask 308 can have an increased line CD compared to the photopatterned metal-containing EUV resist film 306, whereby the dose-to-size can be decreased. In some embodiments, the chemically modified photoresist mask 308 can have an increased density compared to the photopatterned metal-containing EUV resist film 306. In some embodiments, the chemically modified photoresist mask 308 can have an increased etch resistance compared to the photopatterned metal-containing EUV resist film 306. In some embodiments, the chemically modified photoresist mask 308 can have a reduced roughness compared to the photopatterned metal-containing EUV resist film 306.

[0191] As shown in FIG. 3D, the substrate layer 304 is etched using a chemically modified photoresist mask 308 to form concave features defined by the chemically modified photoresist mask 308 in the wafer 300. The wafer 300 undergoes pattern transfer etching, whereby the etchant selectively removes the substrate layer 304 compared to the chemically modified photoresist mask 308. The pattern transfer etching can be performed using dry etching or wet etching. For example, dry etching can utilize a fluorine-based plasma etching process or an oxygen-based plasma etching process. The pattern transfer etching may etch the substrate layer 304 according to the pattern defined by the chemically modified photoresist mask 308. In some embodiments, the chemically modified photoresist mask 308 retains or at least substantially retains an increased line CD after the pattern transfer etching. This indicates that one or more new material properties (e.g., increased line CD) due to chemical treatment are maintained during the pattern transfer etching.

[0192] Selective deposition process In some embodiments, a metal-containing photoresist mask can be exposed to one or more reactive gas species to selectively deposit a protective layer on the metal-containing photoresist mask. Some of the reactive gas species described above can react with the metal-containing photoresist mask and change the material properties by changing the chemical composition of the metal-containing photoresist mask, while some reactive gas species can deposit a material on the metal-containing photoresist mask. In some cases, the deposition of the material proceeds by selectively reacting with the surface of the metal-containing photoresist mask as compared to the substrate layer of the substrate, thereby forming a protective layer on the metal-containing photoresist mask. In some cases, the deposition of the material can proceed by promoting the reaction between gas reactants or by decomposing the gas reactants on the surface of the metal-containing photoresist mask to form a protective layer on the metal-containing photoresist mask. In some cases, the deposition of the material can proceed by converting the outer surface to form reaction sites where the reactive gas species can deposit the material. Regardless of how the deposition proceeds, the deposition can be driven by a thermal-assisted reaction, a plasma-assisted reaction, or both a thermal-assisted reaction and a plasma-assisted reaction. The protective layer may include oxides such as carbon (e.g., boron-doped carbon) or carbides, nitrides (e.g., boron nitride), sulfides, fluorides, metal oxides (e.g., iron oxide), or elemental metal (e.g., tungsten) layers.

[0193] A protective layer can be selectively deposited on a metal-containing photoresist mask to increase line CD and reduce the dose-to-size. Alternatively, a protective layer can be deposited on a metal-containing photoresist mask and the line CD can be maintained during subsequent processing. The protective layer provides one or more materials that are non-volatile during subsequent pattern transfer etching on the surface of the metal-containing photoresist mask. The resulting photoresist mask is more resistant to etching and the selectivity between the photoresist mask and the surrounding material is increased. The protective layer can serve to passivate the photoresist mask. Thus, the line CD can be maintained or substantially maintained after pattern transfer etching. In some cases, a protective layer can be deposited on a metal-containing photoresist mask to reduce roughness (e.g., LWR / LER) or at least maintain the same roughness. In some embodiments, the protective layer can also reduce the occurrence of line breaks / bridging in the metal-containing photoresist mask.

[0194] The protective layer can be formed by introducing a precursor into a process chamber and adsorbing it onto a metal-containing photoresist mask, and then converting the precursor with plasma energy or thermal energy. In some embodiments, the conversion step reacts with an outer portion of the metal-containing photoresist mask to form the protective layer. For example, the precursor may be an organometallic precursor such as an organic precursor or a metal carbonyl precursor. Organic precursors or organometallic precursors typically do not react with conventional polymer-based photoresist materials, but the organic or organometallic precursors of the present disclosure can react with metal-containing or metal-oxide-containing photoresist materials to form a protective film. The organic precursor or organometallic precursor can react with an outer portion of the metal-containing photoresist mask by thermal conversion to form a metal oxide. In other words, the organic precursor or organometallic precursor can deposit a metal oxide on the surface of the metal-containing photoresist mask by a thermal vapor deposition process. Such metal oxides can include, but are not limited to, iron oxide, tungsten oxide, molybdenum oxide, and the like. Examples of thermal vapor deposition processes can include, but are not limited to, physical vapor deposition (PVD), chemical vapor deposition (CVD), and atomic layer deposition (ALD).

[0195] The protective layer can be formed by introducing a metal-containing precursor into a process chamber and converting the metal-containing precursor with plasma energy or thermal energy. For example, the metal-containing precursor may include metal halides such as tungsten hexafluoride, molybdenum hexafluoride, tin tetrachloride, or molybdenum chloride. Other metal-containing precursors can have various ligands. Examples of such metal-containing precursors can include tin tetrakis(dimethylamide), hafnium tetrakis(dimethylamide), dimethylaluminum, trimethylaluminum, and titanium isopropoxide. As described above, the metal-containing precursor can react with the metal-containing photoresist mask by diffusing into the photoresist mask and change the chemical composition of the metal-containing photoresist mask. However, in some embodiments, the metal-containing precursor can alternatively or additionally deposit a protective layer on the surface of the metal-containing photoresist mask. Metal-containing precursors such as tungsten hexafluoride typically do not react with conventional polymer-based photoresist materials, but the metal-containing precursors of the present disclosure can react with metal-containing or metal-oxide-containing photoresist materials to form a protective film. The metal-containing precursor can react with the outer portion of the metal-containing photoresist mask by thermal conversion to form a metal oxide or pure metal layer. Thus, the protective layer of the metal oxide or pure metal layer can be deposited on the metal-containing photoresist mask by thermal PVD, CVD, ALD, or other thermal vapor deposition processes.

[0196] The protective layer may be formed by a plasma-based deposition process. One or more reactant gases can be flowed into the process chamber and adsorbed onto the metal-containing photoresist mask. In some embodiments, a plasma can be ignited within the process chamber to drive the reaction between reactive species and form a protective layer on the metal-containing photoresist mask. In some embodiments, the plasma is ignited remotely from the process chamber, and thus one or more plasma-activated species are introduced into the process chamber to react at the surface of the metal-containing photoresist mask, thereby forming a protective layer on the metal-containing photoresist mask. Thus, the protective layer can be deposited using in-situ plasma or remote plasma. The protective layer may be deposited by plasma-enhanced chemical vapor deposition (PECVD), plasma-enhanced atomic layer deposition (PEALD), ion implantation, or other plasma-based deposition processes. The reactant gases can include, but are not limited to, air, water vapor, hydrogen peroxide, carbon dioxide, carbon monoxide, oxygen, ozone, methane, methanol, ethanol, nitrogen, hydrogen, ammonia, nitrous oxide, nitric oxide, nitrogen dioxide, acetylacetone, formic acid, acetic acid, hydrogen cyanide, boron trichloride, silicon tetrachloride, chlorine, bromine, hydrogen chloride, hydrogen bromide, hydrogen fluoride, hydrogen iodide, fluoromethane, difluoromethane, or combinations thereof. In some embodiments, the protective layer is composed of carbon or carbide. For example, boron-doped carbon can be deposited on a metal-containing or metal-oxide-containing photoresist material using a plasma of a reactant gas containing a mixture of boron trichloride and methane. In some embodiments, the protective layer is composed of nitride. For example, boron nitride can be deposited on a metal-containing or metal-oxide-containing photoresist material using a plasma of a reactant gas containing a mixture of boron trichloride and nitrogen. In some embodiments, the protective layer is composed of elemental metal. As an example, it is possible to deposit a protective layer containing tungsten, titanium, tantalum, ruthenium, aluminum, iron, hafnium, or combinations thereof using a plasma of a metal-containing precursor.In some cases, a protective layer containing a metal oxide (e.g., titanium oxide), a metal nitride (e.g., tungsten nitride), or a metal carbide (e.g., tungsten carbide) may be deposited using a plasma of a metal-containing precursor.

[0197] The protective layer may be selectively deposited on the metal-containing photoresist mask as compared to the surrounding material (e.g., the substrate layer). Selective deposition occurs when the protective layer is preferentially deposited on the metal-containing photoresist mask as compared to the surrounding material. This means that more of the protective layer is deposited on the sidewalls and top surface of the metal-containing photoresist mask than within trenches or gaps that occupy the space between the metal-containing photoresist masks. In other words, selective deposition substantially avoids deposition into the trenches or gaps. Selective deposition can occur when one or more reactive gas species are more reactive with the metal-containing photoresist mask than with the surrounding material. In some cases, selective deposition can be achieved by selectively depositing one or more reactive species on the metal-containing photoresist mask while etching the substrate layer.

[0198] Thermal energy, plasma energy, or a combination of thermal energy and plasma energy can drive the reaction and selectively deposit a protective layer on a metal-containing photoresist mask. By adjusting various process conditions, selective deposition of the protective layer can be achieved. In some embodiments, the substrate temperature during selective deposition of the protective layer may be from about 0 °C to about 400 °C, from about 50 °C to about 300 °C, or from about 100 °C to about 250 °C. In some embodiments, the plasma power during selective deposition of the protective layer may be less than about 6 kW, from about 50 W to about 4000 W, from about 50 W to about 1000 W, or from about 100 W to about 500 W. Other process conditions such as plasma frequency, exposure time, bias voltage, pressure, and flow rate can be adjusted to facilitate selective deposition of the protective layer. In some embodiments, a bias voltage of less than about 800 V, from about 0 V to about 500 V, from about 10 V to about 400 V, or from about 30 V to about 300 V can be applied. In some embodiments, exposure to one or more reactive gas species for selective deposition can proceed over a period of from about 1 second to about 10 minutes, from about 5 seconds to about 8 minutes, or from about 30 seconds to about 4 minutes. In some embodiments, the chamber pressure may be from about 0.1 Torr to about 760 Torr, or in some cases from about 1 mTorr to about 100 mTorr. The first reactive gas species can be flowed into the process chamber at a flow rate of from about 1 sccm to about 1000 sccm, from about 2 sccm to about 500 sccm, or from about 5 sccm to about 300 sccm. The optional second reactive gas species can be co-flowed into the process chamber at a flow rate of from about 5 sccm to about 1000 sccm, from about 10 sccm to about 500 sccm, or from about 20 sccm to about 300 sccm. The optional inert gas species can be co-flowed into the process chamber at a flow rate of from about 20 sccm to about 2000 sccm, from about 30 sccm to about 1000 sccm, or from about 50 sccm to about 500 sccm. As an example, boron trichloride can be flowed into the process chamber at a flow rate of from about 0 sccm to about 80 sccm, and methane can be co-flowed into the process chamber at a flow rate of from about 0 sccm to about 80 sccm. The plasma is ignited using a plasma power of about 100 W.The exposure of boron trichloride and methane to the plasma is carried out over a period of about 5 seconds to about 40 seconds, and the substrate temperature is maintained at about 120 °C. The plasma of boron trichloride and methane reacts with the EUV photoresist mask and selectively deposits boron-doped carbon on the EUV photoresist mask. The EUV photoresist mask may exhibit a reduction in roughness, an increase in line CD, and an increase in etching resistance during subsequent pattern transfer etching.

[0199] Figures 4A-4D show schematic cross-sectional views of various processing steps including the development and processing of a photoresist, and a protective film is selectively deposited on the photoresist by the processing. As shown in Figure 4A, the wafer 400 includes a substrate 402 and a substrate layer 404 to be etched. The wafer 400 further includes a photo-patterned metal-containing EUV resist film 406. For example, the photo-patterned metal-containing EUV resist film 406 may be an organometallic-containing layer disposed on the substrate layer 404 to be etched. The photo-patterned metal-containing EUV resist film 406 may be provided in the process chamber after photo-patterning with an EUV scanner and / or after PEB processing. The photo-patterned metal-containing EUV resist film 406 includes a non-EUV exposure region 406a and an EUV exposure region 406b.

[0200] As shown in Figure 4B, the non-EUV exposure region 406a of the photo-patterned metal-containing EUV resist film 406 is removed in the development process. For development, wet development chemicals or dry development chemicals can be used. The photoresist mask of the photo-patterned metal-containing EUV resist film 406 is formed by removing the non-EUV exposure region 406a after development. Although Figures 4A-4D illustrate negative development, it will be understood that positive development can be applied instead in the present disclosure.

[0201] As shown in FIG. 4C, a protective film 410 is selectively deposited on a photoresist mask of a photopatterned metal-containing EUV resist film 406. The protective film 410 can be selectively deposited on the upper surface and sidewalls of the photopatterned metal-containing EUV resist film 406. The protective film 410 avoids deposition on the surface of the substrate layer 404. In this way, there is no or substantially no protective film 410 in the trenches or gaps defined by the photoresist mask of the photopatterned metal-containing EUV resist film 406. Most of the photopatterned metal-containing EUV resist film 406 remains the same composition after the deposition of the protective film 410.

[0202] In some embodiments, the protective film 410 includes a carbon film such as a boron-doped carbon film. In some embodiments, the protective film 410 includes a nitride film such as a boron nitride film. In some embodiments, the protective film 410 includes an elemental metal, and the metal can include tungsten, molybdenum, hafnium, titanium, ruthenium, iron, or combinations thereof. In some cases, the protective film 410 includes an oxide such as a metal oxide. In some embodiments, the protective film 410 includes a sulfide. In some embodiments, the protective film 410 includes a fluoride. The gas reactants can be flowed into the process chamber toward the wafer 400. The gas reactants can react with each other or react with the photopatterned metal-containing EUV resist film 406 and selectively deposit on the exposed surface of the photopatterned metal-containing EUV resist film 406. Exemplary gas reactants can include oxygen-containing gases, carbon-containing gases, hydrogen-containing gases, nitrogen-containing gases, halogen-containing gases, metal-containing gases, or combinations thereof. It is possible to flow organic gas species, organometallic gas species, metal-containing gas species, or other reactive gas species into the process chamber to selectively deposit the protective film 410.

[0203] In some embodiments, the protective film 410 is deposited at a high temperature such that the deposition is thermally driven. At high temperatures, the deposition of the protective film 410 involves a heat treatment. In some embodiments, the protective film 410 is deposited under plasma exposure, in-situ plasma exposure, or remote plasma exposure. Radicals and / or ions of reactive gas species can facilitate the selective deposition of the protective film 410 onto the photopatterned metal-containing EUV resist film 406. Thus, plasma exposure promotes the deposition of the protective film 410. In some cases, plasma exposure enhances the selectivity of the deposition of the protective film 410 onto the photopatterned metal-containing EUV resist film 406 compared to the substrate layer 404.

[0204] The protective film 410 may passivate the photopatterned metal-containing EUV resist film 406. The protective film 410 can increase the etching resistance to the photopatterned metal-containing EUV resist film 406. Thereby, material loss in the photopatterned metal-containing EUV resist film 406 is prevented, and thus the line CD is maintained or at least substantially maintained during etching. In some embodiments, the protective film 410 may maintain or reduce the roughness in the photopatterned metal-containing EUV resist film 406. In some embodiments, the protective film 410 may maintain or increase the line CD in the photopatterned metal-containing EUV resist film 406, thereby reducing the dose-to-size. In some embodiments, the protective film 410 reduces gas emissions such as the gas emission of tin.

[0205] As shown in FIG. 4D, the substrate layer 404 is etched using a metal-containing EUV resist film 406 that is photopatterned as a mask to form a concave feature on the wafer 300. The wafer 400 undergoes pattern transfer etching, whereby the etchant selectively removes the substrate layer 404 compared to the photoresist mask of the metal-containing EUV resist film 406 that has been photopatterned. The pattern transfer etching can be performed using dry etching or wet etching. In some embodiments, the protective film 410 holds or at least substantially holds the line CD of the metal-containing EUV resist film 406 that has been photopatterned after the pattern transfer etching.

[0206] FIGS. 5A-5D show cross-sectional schematic views of various processing steps including the development and treatment of a photoresist, where one or more properties of the photoresist are changed by the processing and a protective layer is selectively deposited on the photoresist. As shown in FIG. 5A, the wafer 500 includes a substrate 502 and a substrate layer 504 to be etched. The wafer 500 further includes a photopatterned metal-containing EUV resist film 506. For example, the photopatterned metal-containing EUV resist film 506 may be an organometal-containing layer disposed on the substrate layer 504 to be etched. The photopatterned metal-containing EUV resist film 506 may be provided in a process chamber after photopatterning with an EUV scanner and / or after PEB processing. The photopatterned metal-containing EUV resist film 506 includes a non-EUV exposure region 506a and an EUV exposure region 506b.

[0207] As shown in FIG. 5B, the non-EUV exposure region 506a of the photopatterned metal-containing EUV resist film 506 is removed in the development process. For development, a wet development chemical or a dry development chemical can be used. The photoresist mask of the photopatterned metal-containing EUV resist film 506 is formed by removing the non-EUV exposure region 506a after development. FIGS. 5A-5D illustrate negative development, but it will be understood that positive development can be applied instead in the present disclosure.

[0208] As shown in FIG. 5C, the developed photoresist mask can be subjected to a process that changes one or more material properties to produce a chemically modified photoresist mask 508, and a protective film 510 is selectively deposited on the chemically modified photoresist mask 508. The chemically modified photoresist mask 508 has a chemical composition different from that of the photopatterned metal-containing EUV resist film 506. Further, the protective film 510 is selectively deposited on the upper surface and sidewalls of the chemically modified photoresist mask 508 while avoiding deposition on the surface of the substrate layer 504. There is no or substantially no protective film 510 in the trenches or gaps defined by the chemically modified photoresist mask 508. Organic gas species, organometallic gas species, metal-containing gas species, and other reactive gas species can react with the photopatterned metal-containing EUV resist film 506. The reactive gas species of the present disclosure utilize the chemical properties of the photopatterned metal-containing EUV resist film 506 to produce a chemically modified photoresist mask 508 and simultaneously deposit the protective film 510.

[0209] In some embodiments, the reactive gas species react with the metal-containing EUV resist film 506 that has been photopatterned at a high temperature, whereby the reaction is thermally driven. The chemically modified photoresist mask 508 and the protective film 510 can be formed under heat treatment and chemical treatment. In some embodiments, the reactive gas species react with the metal-containing EUV resist film 506 that has been photopatterned under plasma exposure, in-situ plasma exposure, or remote plasma exposure. Radicals and / or ions of the reactive gas species can facilitate the deposition of the protective film 510 and the conversion of the photopatterned metal-containing EUV resist film 506 into the chemically modified photoresist mask 508. The chemically modified photoresist mask 508 and the protective film 510 can be formed under plasma treatment and chemical treatment. In some embodiments, the plasma exposure promotes the conversion and enhances the selectivity of the deposition of the protective film 510 onto the chemically modified photoresist mask 508 compared to the substrate layer 504.

[0210] In some embodiments, the protective film 510 includes a metal-containing film such as a carbon film, a carbide film, a nitride film, a sulfide film, a fluoride film, an oxide film, or an elemental metal film, and the metal of the metal-containing film can include tungsten, molybdenum, hafnium, titanium, ruthenium, iron, or combinations thereof. In some embodiments, the protective film 510 includes a metal oxide. Reactive gas species including an oxygen-containing gas, a carbon-containing gas, a hydrogen-containing gas, a nitrogen-containing gas, a halogen-containing gas, a metal-containing gas, or combinations thereof can react with each other and / or react with the photopatterned metal-containing EUV resist film 506 to selectively deposit the protective film 510 and form the chemically modified photoresist mask 508.

[0211] The chemically modified photoresist mask 508 having the protective film 510 may exhibit one or more new material properties as compared to the photopatterned metal-containing EUV resist film 506. In some embodiments, the chemically modified photoresist mask 508 having the protective film 510 may have an increased line CD as compared to the photopatterned metal-containing EUV resist film 506, thereby reducing the dose-to-size. In some embodiments, the chemically modified photoresist mask 508 having the protective film 510 may have an increased density as compared to the photopatterned metal-containing EUV resist film 506. The protective film 510 may passivate the chemically modified photoresist mask 508. In some embodiments, the chemically modified photoresist mask 508 and the protective film 510 may have increased etch resistance as compared to the photopatterned metal-containing EUV resist film 506. This prevents material loss in the chemically modified photoresist mask 508, and thus the line CD is maintained or at least substantially maintained during etching. In some embodiments, the chemically modified photoresist mask 508 and the protective film 510 may have reduced roughness as compared to the photopatterned metal-containing EUV resist film 506. In some embodiments, the chemically modified photoresist mask 508 can reduce gas evolution, such as a reduction in the gas evolution of tin.

[0212] As described above, post-development processing of the metal-containing photoresist mask can involve one or more approaches (e.g., heat, plasma, chemical, deposition) to achieve a number of specific advantages. Some or all of these approaches can reduce defects or line breaks, increase density, reduce roughness, decrease gas evolution, achieve better etch resistance, increase line CD, and / or decrease dose-to-size. The performance of a metal-containing photoresist mask, such as a metal oxide-containing EUV photoresist mask, can be determined by its dose-to-size, roughness, etch resistance, defects, and line breaks. Some of these improvements will be described in detail below with reference to FIGS. 6-9.

[0213] FIG. 6 shows a schematic cross-sectional view illustrating post-development processing of a photoresist for descumming according to some embodiments. Substrate 600 includes a patterned metal-containing photoresist mask 610 after wet or dry development. After wet or dry development, scum may be present on a portion of substrate 600. The scum may take the form of particles or clusters 620 of metal oxide (e.g., SnO x ) that occupy the unmasked regions of substrate 600. As wet or dry development proceeds, the clusters of metal oxide become more concentrated. Development is generally selective with respect to the removal of organic materials, allowing particles or clusters 620 to remain on the surface of substrate 600 as scum. Some of particles or clusters 620 occupy the trenches or gaps of the patterned metal-containing photoresist mask 610, and some of particles or clusters 620 remain on the sidewalls of the patterned metal-containing photoresist mask 610, leading to an increase in roughness.

[0214] The substrate 600 may be exposed to post-development processing for descumming. In some embodiments, the post-development processing includes thermally annealing the substrate 600 to remove particles or clusters 620. The thermal annealing of the substrate 600 may expose the substrate 600 to a temperature of about 50 °C or higher, about 100 °C or higher, about 100 °C to about 300 °C, or about 100 °C to about 250 °C. In some embodiments, the post-development processing includes exposing the substrate 600 to a plasma to remove particles or clusters 620. The plasma treatment may expose the substrate 600 to an inert gas plasma such as a helium plasma or an argon plasma. Alternatively, the plasma treatment may expose the substrate 600 to a reactive gas plasma. The plasma treatment can cure and densify the patterned metal-containing photoresist mask 610 to remove particles or clusters 620 for descumming and smooth the sidewalls of the patterned metal-containing photoresist mask 610.

[0215] FIG. 7 shows a cross-sectional schematic view illustrating post-development processing of a photoresist for reducing LWR / LER according to some embodiments. The substrate 700 includes a patterned metal-containing photoresist mask 710 after wet or dry development. The edges of the mask may not be straight after development, leading to a deviation from linearity. The deviation from linearity in the mask forms non-linearity in the patterned features, which adversely affects the performance of the device. Such a deviation from linearity can be characterized in the mask as LWR / LER. In some cases, the LWR / LER in the patterned metal-containing photoresist mask 710 may be at least partially due to undesirable defects such as scum on the sidewalls of the patterned metal-containing photoresist mask 710.

[0216] The substrate 700 may be exposed to a post-development treatment to reduce LWR / LER. As shown in FIG. 7, the patterned metal-containing photoresist mask 710 exhibits smooth sidewalls and surfaces after the post-development treatment. Thermal annealing of the substrate 700 can reduce LWR / LER in the patterned metal-containing photoresist mask 710 by exposing the substrate 700 to a temperature of about 50° C. or higher, about 100° C. or higher, about 100° C. to about 300° C., or about 100° C. to about 250° C. In some embodiments, reducing LWR / LER in the patterned metal-containing photoresist mask 710 can be achieved by exposing the substrate 700 to plasma. In some embodiments, a protective film can be selectively deposited on the patterned metal-containing photoresist mask 710 to reduce LWR / LER.

[0217] FIG. 8 shows a cross-sectional schematic view of a post-development treatment of a photoresist for increasing line CD by chemical reaction with a reactive gas species, according to some embodiments. The substrate 800 includes a patterned metal-containing photoresist mask 810 after wet or dry development. Improvement in lithography performance can be correlated with a decrease in the dose-to-size of the patterned metal-containing photoresist mask 810. The dose-to-size is at least partially determined based on the target line CD. Instead of reducing the radiation dose (mJ / cm 2 ) for a particular line CD to reduce the dose-to-size, some post-development treatments can increase the line CD while reducing the dose-to-size by applying the same radiation dose.

[0218] The substrate 800 can be exposed to various reactive gas species and reacted with the patterned metal-containing photoresist mask 810 to increase the line CD. The reactive gas species can interact with the patterned metal-containing photoresist mask 810 in a form that changes the chemical composition of the patterned metal-containing photoresist mask 810. Thereby, a chemically modified photoresist mask 820 having an expanded line CD is formed. The line CD can increase by about 5% or more, about 10% or more, about 15% or more, about 20% or more, or about 25% or more. In some cases, the reaction of the reactive gas species for expanding the line CD with the patterned metal-containing photoresist mask 810 can be promoted by thermal energy and / or plasma energy.

[0219] FIG. 9 shows a schematic cross-sectional view showing a post-development treatment of a photoresist for increasing the line CD with a selectively deposited protective layer according to some embodiments. The substrate 900 includes a patterned metal-containing photoresist mask 910 after wet or dry development. A protective film 920 can be selectively deposited on the upper surface and sidewalls of the patterned metal-containing photoresist mask 910 as compared to the materials surrounding the substrate 900. Various reactive gas species can react with each other or with the exposed surface of the patterned metal-containing photoresist mask 910 to form the protective film 920. The protective film 920 provides an expanded line CD for the patterned metal-containing photoresist mask 910. The line CD can increase by about 5% or more, about 10% or more, about 15% or more, about 20% or more, or about 25% or more. In some cases, the deposition of the protective film 920 and the selectivity of the deposition on the exposed surface of the patterned metal-containing photoresist mask 910 can be promoted by thermal energy and / or plasma energy.

[0220] Device The apparatus of the present disclosure is configured for post-development processing of a patterned metal-containing photoresist mask. The apparatus can be configured for other processing operations such as deposition, bevel and backside cleaning, post-application bake, EUV scanning, post-exposure bake, development, etching, and other operations. In some embodiments, the apparatus is configured to perform a plurality of dry operations. In some embodiments, the apparatus is configured to perform a combination of wet and dry operations. The apparatus may include a single wafer chamber or multiple stations within the same process chamber. Using multiple stations within the same process chamber, it is possible to perform various processing operations as described in the present disclosure at different stations within the same process chamber. In some embodiments, the process chamber for post-development processing of the present disclosure can be performed within the same chamber as development, within the same chamber as pattern transfer etching, or within the same chamber as both development and pattern transfer etching.

[0221] An apparatus configured to perform post-development processing includes a process chamber having a substrate support. The apparatus can at least include a reactive gas source in fluid communication with the process chamber. The apparatus may include one or more gas lines for feeding one or more reactive gas species. In some embodiments, the one or more reactive gas species may include an organic gas species, an organometallic gas species, a metal-containing gas species, or a combination thereof. In some embodiments, the one or more reactive gas species may include an oxygen-containing gas, a carbon-containing gas, a hydrogen-containing gas, a nitrogen-containing gas, a halogen-containing gas, or a combination thereof. The one or more reactive gas species are fed into the process chamber via one or more gas lines and can process a metal-containing photoresist mask after development. The apparatus may include one or more heating elements for temperature control. Such heating elements may be provided within the process chamber and / or within the substrate support. Or such heating elements can also be provided outside the process chamber. In some embodiments, the apparatus may include a plasma source for generating plasma during the processing of the metal-containing photoresist mask after development. In some embodiments, the one or more reactive species can selectively deposit a protective film on the metal-containing photoresist mask after development. The apparatus may further include one or more sensors for sensing the number of particles, the number of wafers, the number of thicknesses, or other parameters for triggering the end point of the post-development processing.

[0222] FIG. 10 illustrates a schematic diagram of an exemplary process station for maintaining an environment suitable for performing photoresist development, photoresist processing, and / or etching operations, according to some embodiments. A plurality of process stations 1000 may be included in a common low-pressure process tool environment. For example, FIG. 11 illustrates one embodiment of a multi-station processing tool 1100, such as a VECTOR® processing tool available from Lam Research Corporation of Fremont, California. In some embodiments, one or more hardware parameters of the process station 1100 (including those described in detail below) can be programmatically adjusted by one or more computer controllers 1150.

[0223] The process station can be configured as a module within a cluster tool. FIG. 13 illustrates a semiconductor process cluster tool architecture having vacuum integration deposition and patterning modules suitable for implementation of the embodiments described herein. Such a cluster process tool architecture can include a resist deposition module, a resist exposure (EUV scanner) module, a resist development module, a resist rework module, and an etching module, as described above and further described below with reference to FIGS. 12 and 13.

[0224] Returning to FIG. 10, the process station 1000 is in fluid communication with a reactant delivery system 1001 for delivering a process gas to a showerhead 1006. The reactant delivery system 1001 optionally includes a mixing vessel 1004 for blending and / or conditioning the process gas delivered to the showerhead 1006. One or more mixing vessel inlet valves 1020 can control the introduction of the process gas into the mixing vessel 1004. When plasma exposure is used, the plasma can also be delivered to the showerhead 1006 or generated at the process station 1000. As noted above, in at least some embodiments, non-plasma thermal exposure is preferred.

[0225] Figure 10 includes an optional vaporization point 1003 for vaporizing the liquid reactant supplied to the mixing vessel 1004. In some embodiments, a liquid flow controller (LFC) can be provided upstream of the vaporization point 1003 to control the mass flow rate of the liquid that is vaporized and fed to the process station 1000. For example, the LFC can include a thermal mass flow meter (MFM) located downstream of the LFC. Next, the plunger valve of the LFC can be adjusted in response to a feedback control signal provided by a proportional integral derivative (PID) controller that is in electrical communication with the MFM.

[0226] The showerhead 1006 distributes the process gas toward the substrate 1012. In the embodiment shown in FIG. 10, the substrate 1012 is located below the showerhead 1006 and is shown stationary on the pedestal 1008. The showerhead 1006 can have any suitable shape and can have any suitable number and arrangement of ports for distributing the process gas to the substrate 1012.

[0227] In some embodiments, the pedestal 1008 can be raised or lowered to expose the substrate 1012 to the volume between the substrate 1012 and the showerhead 1006. It will be appreciated that in some embodiments, the height of the pedestal can be programmatically adjusted by a suitable computer controller 1050. In some embodiments, the showerhead 1006 can have a plurality of plenum volumes with a plurality of temperature control sections.

[0228] In some embodiments, the pedestal 1008 can be temperature controlled via a heater 1010. In some embodiments, the pedestal 1008 can be heated to a temperature above 0°C to a maximum of 300°C, such as 50°C to 280°C, such as about 100°C to 240°C, during post-development processing as described in the disclosed embodiments. In some embodiments, the heater 1010 of the pedestal 1008 can include a plurality of independently controllable temperature control zones.

[0229] Further, in some embodiments, pressure control for the process station 1000 can be provided by the butterfly valve 1018. As shown in the embodiment of FIG. 10, the butterfly valve 1018 throttles the vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, pressure control of the process station 1000 can also be adjusted by changing the flow rate of one or more gases introduced into the process station 1000.

[0230] In some embodiments, the position of the showerhead 1006 can be adjusted relative to the pedestal 1008 to vary the volume between the substrate 1012 and the showerhead 1006. Further, it will be appreciated that the vertical position of the pedestal 1008 and / or the showerhead 1006 may be varied by any suitable mechanism within the scope of the present disclosure. In some embodiments, the pedestal 1008 may include a rotational axis for rotating the orientation of the substrate 1012. It will be appreciated that one or more of these exemplary adjustments can be implemented programmatically by one or more suitable computer controllers 1050.

[0231] When plasma can be used, for example, in a descum, process, deposition, or planarization operation, the showerhead 1006 and the pedestal 1008 are in electrical communication with a radio frequency (RF) power source 1014 and a matching network 1016 to supply power to the plasma. In some embodiments, the plasma energy can be controlled by controlling one or more of the process station pressure, gas concentration, RF source power, RF source frequency, and plasma power pulse timing. For example, the RF power source 1014 and the matching network 1016 can operate at any suitable power to form a plasma having a desired composition of radical species. An example of suitable power is up to about 1000 W.

[0232] In some embodiments, instructions for the controller 1050 may be provided via input / output control (IOC) sequence instructions. In one example, instructions for setting conditions for a process step may be included in the corresponding recipe step of the process recipe. Optionally, the process recipe steps may be arranged in sequence such that all instructions for a process step are executed simultaneously with that process step. In some embodiments, instructions for setting one or more reactor parameters may be included in a recipe step. For example, a recipe step may include instructions for setting the flow rate of an etching gas such as hydrogen halide, and a time delay instruction for the recipe step. In some embodiments, the controller 1050 may include any of the features described below with respect to the controller 1150 of FIG. 11.

[0233] As described above, one or more process stations can be included in the multi-station processing tool. FIG. 11 shows a schematic diagram of one embodiment of a multi-station processing tool 1100 having an inbound load lock 1102 and an outbound load lock 1104, either or both of which may include a remote plasma source. Robot 1106 is configured to move wafers from a cassette loaded via pod 1108 at atmospheric pressure to inbound load lock 1102 via atmospheric port 1110. The wafer is placed on pedestal 1112 of inbound load lock 1102 by robot 1106, atmospheric port 1110 is closed, and the load lock is pumped down. If inbound load lock 1102 includes a remote plasma source, the wafer may undergo remote plasma processing to treat the substrate surface within the load lock before being introduced into process chamber 1114. Further, the wafer may also be heated in inbound load lock 1102, for example, to remove moisture and absorbed gas. Next, chamber transfer port 1116 to process chamber 1114 is opened, and another robot (not shown) places the wafer on the pedestal of the first station shown within the reactor for processing. Although the embodiment illustrated in FIG. 11 includes load locks, it will be understood that in some embodiments, wafers may be directly accessed to the process station.

[0234] The illustrated processing chamber 1114 includes four process stations numbered from 1 to 4 in the embodiment shown in FIG. 11. Each station has a heating pedestal (shown as 1118 for station 1) and a gas line inlet. It will be appreciated that in some embodiments, each process station may have different purposes or multiple purposes. For example, in some embodiments, the process station may be switchable between a development mode and an etching process mode. Additionally or alternatively, in some embodiments, the processing chamber 1114 may include one or more corresponding pairs of development and etching process stations. Although the illustrated processing chamber 1114 includes four stations, it will be understood that a processing chamber according to the present disclosure may have any suitable number of stations. For example, in some embodiments, the processing chamber may have five or more stations, and in other embodiments, the processing chamber may have three or fewer stations.

[0235] FIG. 11 illustrates one embodiment of a wafer handling system 1190 for transferring wafers within the processing chamber 1114. In some embodiments, the wafer handling system 1190 can transfer wafers between various process stations and / or between a process station and a load lock. It will be understood that any suitable wafer handling system may be used. Non-limiting examples include a wafer carousel and a wafer handling robot. FIG. 11 also illustrates one embodiment of a controller 1150 (e.g., a system controller) used to control the process conditions and hardware state of the process tool 1100. The controller 1150 can include one or more memory devices 1156, one or more mass storage devices 1154, and one or more processors 1152. The processor 1152 can include a CPU or computer, analog and / or digital input / output connections, a stepping motor controller board, and the like.

[0236] In some embodiments, the controller 1150 controls all of the activities of the process tool 1100. The controller 1150 executes system control software 1158 that is stored in the mass storage device 1154, loaded into the memory device 1156, and executed by the processor 1152. Alternatively, the control logic may be hard-coded in the controller 1150. Application specific integrated circuits, programmable logic devices (e.g., field programmable gate arrays, or FPGAs), etc. can be used for these purposes. In the following description, whenever "software" or "code" is used, functionally equivalent hard-coded logic can always be used instead. The system control software 1158 may include instructions for controlling timing, gas mixing, gas flow rate, chamber pressure and / or station pressure, chamber temperature and / or station temperature, wafer temperature, target power level, RF power level, substrate pedestal, chuck position and / or susceptor position, and other parameters of a particular process implemented by the process tool 1100. The system control software 1158 may be configured in any suitable manner. For example, various process tool component subroutines or control objects may be written to control the operation of the process tool components used to execute various process tool processes. The system control software 1158 may be coded in any suitable computer-readable programming language.

[0237] In some embodiments, the system control software 1158 may include input / output control (IOC) sequence instructions for controlling the various parameters described above. In some embodiments, other computer software and / or programs stored in the mass storage device 1154 and / or the memory device 1156 associated with the controller 1150 may be used. Examples of programs or sections of programs for this purpose include a substrate positioning program, a process gas control program, a pressure control program, a heater control program, and a plasma control program.

[0238] The substrate positioning program can include program code for process tool components used to load a substrate onto pedestal 1118 and control the spacing between the substrate and other parts of process tool 1100.

[0239] The process gas control program can include code for controlling the process gas composition and flow rate to stabilize the pressure of the process station, and optionally code for flowing gas to one or more process stations prior to deposition. The pressure control program can include, for example, code for controlling the pressure of the process station by adjusting a throttle valve of the exhaust system of the process station, the gas flow to the process station, etc.

[0240] The heater control program can include code for controlling the current to a heating unit used to heat the substrate. Alternatively, the heater control program can control the delivery of a heat transfer gas (such as helium) to the substrate.

[0241] The plasma control program can include code for setting the RF power level applied to the process electrodes within one or more process stations according to the embodiments of this specification.

[0242] The pressure control program can include code for maintaining the pressure within the reaction chamber according to the embodiments of this specification.

[0243] In some embodiments, a user interface associated with controller 1150 may be present. The user interface can include a display screen, a graphical software display of the device and / or process conditions, and user input devices such as a pointing device, keyboard, touch screen, microphone, etc.

[0244] In some embodiments, the parameters adjusted by the controller 1150 may relate to process conditions. Non-limiting examples include process gas composition and flow rate, temperature, pressure, plasma conditions (such as RF bias power level), etc. These parameters may be provided to the user in the form of a recipe and can be input using a user interface.

[0245] Signals for monitoring the process may be provided by various process tool sensors to the analog and / or digital input connections of the controller 1150. Signals for controlling the process can be output at the analog and digital output connections of the process tool 1100. Non-limiting examples of process tool sensors that can be monitored include mass flow controllers, pressure sensors (such as pressure gauges), thermocouples, etc. Appropriately programmed feedback and control algorithms can be used with the data from these sensors to maintain process conditions.

[0246] The controller 1150 can provide program instructions for performing the deposition process described above. The program instructions can control various process parameters such as DC power level, RF bias power level, pressure, temperature, etc. The instructions can control the parameters for operating development, cleaning, and / or etching processes according to the various embodiments described herein.

[0247] The controller 1150 typically includes one or more memory devices and one or more processors configured to execute instructions to implement the method according to the disclosed embodiments. A machine-readable medium containing instructions for controlling process operations according to the disclosed embodiments may be coupled to the controller 1150.

[0248] In some embodiments, the controller 1150 is part of a system, and such a system may be part of the examples described above. Such a system can include semiconductor processing equipment including one or more processing tools, one or more chambers, one or more processing platforms, and / or specific processing components (such as wafer pedestals, gas flow systems, etc.). These systems may be integrated with electronics for controlling system operation before, during, and after processing of a semiconductor wafer or substrate. Such electronics may be referred to as a "controller" and may control various components or subcomponents of one or more systems. The controller 1150 may be programmed to control any of the processes disclosed herein, depending on the processing conditions and / or the type of system. Such processes include delivery of process gases, temperature setting (e.g., heating and / or cooling), pressure setting, vacuum setting, power setting, radio frequency (RF) generator setting, RF matching circuit setting, frequency setting, flow rate setting, fluid delivery setting, position and motion setting, loading and unloading of wafers to and from tools connected or coupled to a particular system and other transfer tools, and / or loading and unloading of wafers to and from a load lock.

[0249] In a broad sense, system controller 1150 may be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive commands, issue commands, control operations, enable cleaning operations, enable endpoint measurements, etc. The integrated circuits may include a chip in the form of firmware that stores program instructions, a digital signal processor (DSP), a chip defined as an application specific integrated circuit (ASIC), and / or one or more microprocessors, i.e., a microcontroller that executes program instructions (e.g., software). The program instructions are commands communicated to controller 1150 in the form of various individual settings (or program files) that may define the operating parameters for performing a particular process on or for a semiconductor wafer or for the system. The operating parameters may, in some embodiments, be part of a recipe defined by a process engineer to implement one or more processing steps in the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or wafer dies.

[0250] In some embodiments, the controller 1150 may be part of a computer that is integrated or coupled with the system or otherwise network-connected to the system, or may be coupled to such a computer, or may be a combination thereof. For example, the controller 1150 may be within the "cloud" or may be all or part of a fab host computer system. This enables remote access to wafer processing. The computer can enable remote access to the system, monitor the current progress of the fabrication operation, consider the history of past fabrication operations, consider trends or performance criteria from multiple fabrication operations, change the parameters of the current process, set the process steps following the current process, or initiate a new process. In some examples, a remote computer (e.g., a server) can provide a process recipe to the system over a network. Such a network may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and / or settings, and such parameters and / or settings are then communicated from the remote computer to the system. In some examples, the controller 1150 receives instructions in the form of data. Such data specifies the parameters for each process step to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process being performed and the type of tool that the controller 1150 is configured to interact with or control. Thus, as described above, the controller 1150 may be distributed, for example, by including one or more individual controllers that are network-connected to each other and cooperate towards a common purpose (such as the processes and controls described herein).As an example of a distributed controller for such purposes, one or more integrated circuits on a chamber, which are remotely located (e.g., at the platform level or as part of a remote computer) and communicate with one or more integrated circuits combined to control the process in the chamber, may be mentioned.

[0251] Exemplary systems can include, but are not limited to, plasma etching chambers or modules, deposition chambers or modules, spin rinse chambers or modules, metal plating chambers or modules, cleaning chambers or modules, bevel edge etching chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, ALD chambers or modules, atomic layer etching (ALE) chambers or modules, ion implantation chambers or modules, tracking chambers or modules, EUV lithography chambers (scanners) or modules, development chambers or modules, and any other semiconductor processing systems that may be related to or used in the fabrication and / or manufacture of semiconductor wafers.

[0252] As described above, depending on one or more process steps performed by the tool, the controller 1150 may communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools located throughout the factory, the main computer, another controller, or a tool used for material transport that loads and unloads wafer containers to and from tool locations and / or load ports within a semiconductor manufacturing factory.

[0253] In certain embodiments, an ICP reactor that may be suitable for etching operations suitable for the implementation of some embodiments is described herein. Although the ICP reactor is described herein, it should be understood that in some embodiments, capacitively coupled plasma reactors may also be used.

[0254] FIG. 12 schematically shows a cross-sectional view of an inductively coupled plasma apparatus 1200 suitable for implementing certain embodiments or aspects of embodiments such as dry development, post-development processing, and / or etching, an example of which is the Kiyo® reactor manufactured by Lam Research Corporation of Fremont, California. In other embodiments, it can be implemented using other tools or tool types having functionality for performing the dry development, post-development processing, and / or etching processes described herein.

[0255] The inductively coupled plasma apparatus 1200 includes an integrated process chamber 1224 structurally defined by a chamber wall 1201 and a window 1211. The chamber wall 1201 can be fabricated from stainless steel, aluminum, or plastic. The window 1211 can be fabricated from quartz or other dielectric materials. An optional internal plasma grid 1250 divides the integrated process chamber into an upper sub-chamber 1202 and a lower sub-chamber 1203. In many embodiments, the plasma grid 1250 can be removed, thereby enabling utilization of the chamber space consisting of sub-chambers 1202 and 1203. A chuck 1217 is positioned within the lower sub-chamber 1203 near the bottom inner surface. The chuck 1217 is configured to receive and hold a semiconductor wafer 1219 on which etching and deposition processes are performed. The chuck 1217, if present, can be an electrostatic chuck for supporting the wafer 1219. In some embodiments, an edge ring (not shown) surrounds the chuck 1217 and has an upper surface that is substantially planar with the upper surface of the wafer 1219 when present above the chuck 1217. The chuck 1217 also includes electrostatic electrodes for chucking and de-chucking the wafer 1219. For this purpose, a filter and a DC clamp power supply (not shown) may be provided. Other control systems for lifting the wafer 1219 from the chuck 1217 may also be provided. The chuck 1217 can be charged using an RF power supply 1223. The RF power supply 1223 is connected to a matching circuit 1221 through a connection 1227. The matching circuit 1221 is connected to the chuck 1217 through a connection 1225. In this way, the RF power supply 1223 is connected to the chuck 1217. In various embodiments, the bias power of the electrostatic chuck may be set to about 50V, or may be set to different bias powers depending on the process implemented according to the disclosed embodiments. For example, the bias power may be about 20V to about 100V, or about 30V to about 150V.

[0256] The elements for plasma generation include a coil 1233 positioned above the window 1211. In some embodiments, the coil is not used in the disclosed embodiments. The coil 1233 is fabricated from a conductive material and includes at least one complete turn. The example of the coil 1233 shown in FIG. 12 includes 3 turns. The cross-section of the coil 1233 is indicated by symbols, where the coil with an "X" extends by rotating within the page, while the coil with a "●" extends by rotating out of the page. The elements for plasma generation also include an RF power source 1241 configured to supply RF power to the coil 1233. Generally, the RF power source 1241 is connected to a matching circuit 1239 through a connection 1245. The matching circuit 1239 is connected to the coil 1233 through a connection 1243. In this way, the RF power source 1241 is connected to the coil 1233. An optional Faraday shield 1249 is positioned between the coil 1233 and the window 1211. The Faraday shield 1249 can be maintained at a spaced-apart relationship with respect to the coil 1233. In some embodiments, the Faraday shield 1249 is disposed immediately above the window 1211. In some embodiments, the Faraday shield 1249 is between the window 1211 and the chuck 1217. In some embodiments, the Faraday shield 1249 is not maintained at a spaced-apart relationship with respect to the coil 1233. For example, the Faraday shield 1249 may be directly below the window 1211 without a gap. The coil 1233, the Faraday shield 1249, and the window 1211 are each configured to be substantially parallel to each other. The Faraday shield 1249 can prevent metal or other species from depositing on the window 1211 of the process chamber 1224.

[0257] Process gas can flow into the process chamber through one or more main gas inlets 1260 and / or one or more side gas inlets 1270 positioned in the upper subchamber 1202. Similarly, although not explicitly shown, similar gas inlets can be used to supply process gas to the capacitively coupled plasma processing chamber. A vacuum pump, for example, a single- or two-stage mechanical dry pump and / or a turbomolecular pump 1240 can be used to draw process gas out of the process chamber 1224 and maintain the pressure within the process chamber 1224. For example, a vacuum pump can be used to evacuate the lower subchamber 1203 during a purge operation. To selectively control the application of the vacuum environment provided by the vacuum pump, a valve control conduit can be used to fluidly connect the vacuum pump to the process chamber 1224. This can be done using a closed-loop control flow restriction device such as a throttle valve (not shown) or a pendulum valve (not shown) during the plasma processing operation. Similarly, a vacuum pump and valve control fluid connection to the capacitively coupled plasma processing chamber can also be used.

[0258] During operation of the apparatus 1200, one or more process gases may be supplied through gas inlets 1260 and / or 1270. In certain embodiments, the process gas may be supplied only through the main gas inlet 1260 or only through the side gas inlet 1270. Optionally, the gas inlets shown in the figures may be replaced with more complex gas inlets, such as one or more showerheads. The Faraday shield 1249 and / or optional grid 1250 may include internal channels and holes that allow the process gas to be fed into the process chamber 1224. Either or both of the Faraday shield 1249 and the optional grid 1250 may serve as a showerhead for feeding the process gas. In some embodiments, the liquid vaporization and feed system may be disposed upstream of the process chamber 1224, such that when the liquid reactant or precursor is vaporized, the vaporized reactant or precursor is introduced into the process chamber 1224 through the gas inlets 1260 and / or 1270.

[0259] RF power is supplied from the RF power source 1241 to the coil 1233 to cause an RF current to flow through the coil 1233. The RF current flowing through the coil 1233 generates an electromagnetic field around the coil 1233. The electromagnetic field generates an induced current within the upper subchamber 1202. Physical and chemical interactions between the various generated ions and radicals and the wafer 1219 etch the features of the wafer 1219 and selectively deposit a layer on the wafer 1219.

[0260] When the plasma grid 1250 is used such that both the upper subchamber 1202 and the lower subchamber 1203 are present, the induced current acts on the gas present in the upper subchamber 1202 to generate an electron-ion plasma in the upper subchamber 1202. The optional internal plasma grid 1250 limits the number of hot electrons in the lower subchamber 1203. In some embodiments, the apparatus 1200 is designed and operated such that the plasma present in the lower subchamber 1203 is an ion-ion plasma.

[0261] Both the upper electron-ion plasma and the lower ion-ion plasma can contain positive and negative ions, but the ion-ion plasma has a higher ratio of negative ions to positive ions. Volatile etching and / or deposition by-products can be removed from the lower subchamber 1203 through port 1222. The chuck 1217 disclosed herein can operate at a high temperature in the range of about 10°C to about 250°C. The temperature depends on the process operation and the specific recipe.

[0262] When the apparatus 1200 is installed in a clean room or a fabrication facility, it may be coupled to a facility (not shown). The facility includes piping that provides process gas, vacuum, temperature control, and environmental particle control. These facilities are coupled to the apparatus 1200 when installed in the intended fabrication facility. In addition, the apparatus 1200 can be coupled to a transfer chamber that allows a robot to use typical automated operations to move semiconductor wafers in and out of the apparatus 1200.

[0263] In some embodiments, a controller 1230 (which can include one or more physical or logical controllers) controls some or all of the operation of the process chamber 1224. The controller 1230 can include one or more memory devices and one or more processors. In some embodiments, the apparatus 1200 includes a switching system for controlling flow rate and duration when the disclosed embodiments are implemented. In some embodiments, the apparatus 1200 can have a switching time of up to about 500 ms, or up to about 750 ms. The switching time can depend on the flowing chemical, the selected recipe, the reactor architecture, and other factors.

[0264] In some embodiments, the controller 1230 is part of the system and can be part of the examples described above. Various aspects of the controller 1230 have been described above.

[0265] EUV lithography can be performed using any suitable tool, often referred to as a scanner, such as the TWINSCAN NXE:3300B (registered trademark) platform supplied by ASML of Veldhoven, the Netherlands. The EUV lithography tool may be a stand-alone device for loading and unloading substrates therefrom for the deposition and etching described herein. Alternatively, as described below, the EUV lithography tool may be a module on a larger multi-component tool. FIG. 13 illustrates a semiconductor process cluster tool architecture having a vacuum integrated deposition, EUV patterning, and dry development / etching, and a post-development processing module that interfaces with a vacuum transfer module suitable for implementation of the processes described herein. The process can be performed without such a vacuum integrated device, but such a device may be advantageous in some embodiments.

[0266] FIG. 13 illustrates a semiconductor process cluster tool architecture having a vacuum integrated deposition, patterning, and processing modules that interface with a vacuum transfer module suitable for implementation of the processes described herein. The arrangement of transfer modules for "transferring" wafers between multiple storage facilities and processing modules is sometimes referred to as a "cluster tool architecture" system. Depending on the requirements of a particular process, the deposition, patterning, and processing modules are vacuum integrated. Other modules, such as for etching, can also be included in the cluster.

[0267] The vacuum transfer module (VTM) 1338 interfaces with four processing modules 1320a - 1320d and can be individually optimized to perform various fabrication processes. As an example, the processing modules 1320a - 1320d can be implemented to perform deposition, evaporation, ELD, dry development, cleaning, etching, processing, strip, and / or other semiconductor processes. For example, module 1320a may be an ALD reactor operable to perform non - plasma thermal atomic layer deposition as described herein, such as a Vector tool available from Lam Research of Fremont, California. And module 1320b may be a PECVD tool such as Lam Vector®. It should be understood that the figures are not necessarily drawn to scale.

[0268] The airlocks 1342 and 1346, also known as load locks or transfer modules, interface with the VTM 1338 and the patterning module 1340. For example, as described above, a suitable patterning module can be the TWINSCAN NXE:3300B® platform supplied by ASML of Veldhoven, the Netherlands). This tool architecture enables the transfer of workpieces, such as semiconductor substrates or wafers, under vacuum so as not to react prior to exposure. The integration of the deposition module and the lithography tool is facilitated by the fact that EUVL also requires a significantly reduced pressure, taking into account the strong light absorption of incident photons by ambient gases such as H 2 O, O 2 etc.

[0269] As described above, this integrated architecture is only one possible embodiment of the tools for implementing the described process. The process can also be implemented using more conventional stand-alone EUVL scanners and, as modules, stand-alone or integrated into a cluster architecture with other tools such as etching, stripping, etc. (e.g., Lam Kiyo or Gamma tools) without the integrated patterning module, using deposition reactors such as Lam Vector tools as described with reference to FIG. 13, for example.

[0270] Airlock 1342 can be an "unloading" load lock that refers to the transfer of the substrate from the VTM 1338 that functions the deposition module 1320a to the patterning module 1340, and airlock 1346 can be a "loading" load lock that refers to the transfer of the substrate returning from the patterning module 1340 to the VTM 1338. The loading load lock 1346 can also provide an interface to the outside of the tool for access and exit of the substrate. Each process module has a facet that interfaces the module to the VTM 1338. For example, the deposition process module 1320a has a facet 1336. Within each facet, sensors, such as the illustrated sensors 1 to 18, are used to detect the passage of the wafer 1326 when moving between the respective stations. The patterning module 1340 as well as the airlocks 1342 and 1346 can similarly be provided with additional facets and sensors not shown.

[0271] The main VTM robot 1322 transfers the wafer 1326 between modules including airlocks 1342 and 1346. In one embodiment, the robot 1322 has one arm, and in another embodiment, the robot 1322 has two arms, and each arm has an end effector 1324 for lifting a wafer such as the wafer 1326 for conveyance. The front-end robot 1344 is used therein to transfer the wafer 1326 from the outfeed airlock 1342 to the patterning module 1340 and from the patterning module 1340 to the infeed airlock 1346. The front-end robot 1344 can also convey the wafer 1326 between the infeed load lock and the outside of the tool for access and exit of the substrate. Since the infeed airlock module 1346 has the ability to adapt the environment between atmospheric pressure and vacuum, the wafer 1326 can move between the two pressure environments without being damaged.

[0272] Note that EUVL tools typically operate at a higher vacuum than deposition tools. In this case, it is desirable to increase the vacuum environment of the substrate during transfer between the deposition tool and the EUVL tool to enable outgassing of the substrate before entering the patterning tool. The outfeed airlock 1342 can provide this function by holding wafers transferred at a low pressure not higher than the pressure within the patterning module 1340 over a period of time and discharging off-gas, thereby preventing the optical system of the patterning tool 1340 from being contaminated by off-gas from the substrate. The appropriate pressure for the discharge off-gas airlock is 1E-8 Torr or less.

[0273] In some embodiments, a controller 1350 (which can include one or more physical or logical controllers) controls some or all of the operation of the cluster tool and / or its separate modules. Note that the controller can be local to the cluster architecture, or can be located external to the cluster architecture on the manufacturing floor, or can be located remotely and connected to the cluster architecture via a network. The controller 1350 can include one or more memory devices and one or more processors. The processor can include a central processing unit (CPU) or computer, analog and / or digital input / output connections, a stepper motor controller board, and other similar components. Instructions for performing appropriate control operations are executed on the processor. These instructions can be stored in a memory device associated with the controller or can be provided via a network. In certain embodiments, the system controller executes system control software.

[0274] The system control software can include instructions for controlling the timing of application and / or the magnitude of any aspect of the tool or module operation. The system control software can be configured in any suitable manner. For example, various process tool component subroutines or control objects may be written to control the operation of the process tool components required to execute various process tool processes. The system control software can be coded in any suitable computer-readable programming language. In some embodiments, the system control software includes input / output control (IOC) sequence instructions for controlling the various parameters described above. For example, each stage of a semiconductor manufacturing process can include one or more instructions executed by the system controller. For example, instructions for setting process conditions for condensation, deposition, evaporation, patterning, and / or etching stages may be included in the corresponding recipe stage.

[0275] In various embodiments, an apparatus for post-development processing is provided. The apparatus can include a processing chamber for patterning, processing, deposition, and etching, and a controller including instructions for post-development processing of a patterned photoresist mask. The instructions can include code for processing a metal-containing photoresist mask patterned after development in the processing chamber. Such processing can include heat treatment, plasma treatment, chemical treatment, or selective deposition of a protective layer on the patterned metal-containing photoresist mask.

[0276] Note that a computer controlling wafer movement can be local to a cluster architecture, or can be located external to the cluster architecture of the manufacturing floor, or can be located remotely and connected to the cluster architecture via a network. The controller described above with respect to any of FIGS. 10, 11, or 12 can be implemented using the tool of FIG. 13.

[0277] Conclusion A processing strategy (e.g., post-development processing) for improving EUV lithography performance of a metal-containing EUV resist is disclosed.

[0278] In the foregoing description, numerous specific details are set forth in order to provide a thorough understanding of the presented embodiments. The disclosed embodiments can be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail so as not to unnecessarily obscure the disclosed embodiments. The disclosed embodiments are described in conjunction with specific embodiments, but it will be understood that the disclosed embodiments are not intended to be limiting.

[0279] Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Note that there are many other ways to implement the processes, systems, and apparatuses of this embodiment. Accordingly, this embodiment should be regarded as illustrative and not restrictive, and those embodiments should not be limited to the details described herein.

[0280] The following claims are provided to further illustrate certain embodiments of the present disclosure. The present disclosure is not necessarily limited to these embodiments.

Claims

1. A method of processing a substrate in a process chamber, comprising: providing the substrate in the process chamber, the substrate being a semiconductor substrate comprising a substrate layer and a developed metal-containing photoresist mask on the substrate layer; and processing the developed metal-containing photoresist mask by exposing it to one or more reactive gases. A method as described above.

2. The method according to claim 1, further comprising, after processing the developed metal-containing photoresist mask, etching the substrate layer and forming a concave feature using the developed metal-containing photoresist mask, wherein the critical dimension of the developed metal-containing photoresist mask is maintained during etching. A method as described above.

3. The method according to claim 1, wherein processing the developed metal-containing photoresist mask comprises selectively depositing a protective layer on the developed metal-containing photoresist mask as compared to the substrate layer, wherein the protective layer comprises carbon or carbide, nitride, sulfide, fluoride, oxide, or elemental metal. A method as described above.

4. The method according to claim 3, wherein selectively depositing the protective layer comprises exposing the developed metal-containing photoresist mask to a metal precursor. A method as described above.

5. The method according to claim 4, wherein the metal precursor is generated in-situ in the process chamber. A method as described above.

6. The method according to claim 1, wherein the one or more reactive gases comprise a carbon-containing precursor or a metal halide. A method as described above.

7. The method according to claim 1, wherein processing the developed metal-containing photoresist mask comprises exposing the developed metal-containing photoresist mask to a carbon-containing precursor and selectively depositing a metal-containing layer on the developed metal-containing photoresist mask. A method as described above.

8. The method according to claim 1, wherein processing the developed metal-containing photoresist mask increases one or more of the following material properties: density, etch resistance, and critical dimension of the developed metal-containing photoresist mask. A method as described above.

9. The method according to claim 1, ​ Processing the developed metal-containing photoresist mask includes heat annealing the developed metal-containing photoresist mask at a high temperature of about 100 °C to about 250 °C, a method.

10. The method according to claim 1, wherein processing the developed metal-containing photoresist mask includes exposing the developed metal-containing photoresist mask to the one or more reactive gases in a plasma, a method.

11. The method according to claim 1, further comprising developing the metal-containing photoresist to selectively remove a portion of the metal-containing photoresist to form the developed metal-containing photoresist mask, and developing the metal-containing photoresist includes exposing the metal-containing photoresist to a wet developing chemical or a dry developing chemical, a method.

12. A method of processing a substrate in a process chamber, providing the substrate in the process chamber, wherein the substrate is a semiconductor substrate comprising a substrate layer and a developed metal-containing photoresist mask on the substrate layer, and using one or more of the following operations: (i) heat annealing the developed metal-containing photoresist mask, (ii) exposing the developed metal-containing photoresist mask to a plasma, (iii) exposing the developed metal-containing photoresist mask to one or more reactive gases, and (iv) selectively depositing a protective layer on the developed metal-containing photoresist mask as compared to the substrate layer to process the developed metal-containing photoresist mask including, a method.

13. The method according to claim 12, wherein heat annealing the developed metal-containing photoresist mask includes exposing the developed metal-containing photoresist mask to a high temperature of about 100 °C to about 250 °C and reducing the defect rate and line width roughness (LWR) in the developed metal-containing photoresist mask, a method.

14. The method according to claim 12, wherein exposing the developed metal-containing photoresist mask to a plasma densifies the developed metal-containing photoresist mask to reduce the LWR, a method.

15. The method according to claim 12, Exposing the developed metal-containing photoresist mask to the one or more reactive gases includes exposing the developed metal-containing photoresist mask to carbon monoxide, carbon dioxide, metal carbonyl, organometal, metal halide, or a combination thereof, and increasing the etching resistance and / or critical dimension of the developed metal-containing photoresist mask, method.

16. The method according to claim 12, Selectively depositing the protective layer on the developed metal-containing photoresist mask includes selectively depositing carbon or carbide, nitride, sulfide, fluoride, oxide, or an elemental film, and increasing the critical dimension of the developed metal-containing photoresist mask, method.

17. An apparatus for processing a substrate in a process chamber, A substrate support in the process chamber, the substrate support being configured to support a substrate comprising a substrate layer and a developed metal-containing photoresist mask on the substrate layer; A reactive gas source in fluid communication with the process chamber and configured to feed one or more reactive gases toward the substrate support through one or more gas inlets to process the developed metal-containing photoresist mask Apparatus comprising.

18. The apparatus according to claim 17, One or more heating elements configured to heat the substrate to a high temperature during processing of the developed metal-containing photoresist mask Further comprising.

19. The apparatus according to claim 17, A plasma source configured to generate plasma during processing of the developed metal-containing photoresist mask Further comprising.

20. The apparatus according to claim 17, The reactive gas source configured to feed one or more reactive gases is configured to selectively deposit a protective film on the developed metal-containing photoresist mask during processing of the developed metal-containing photoresist mask, apparatus.

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