In-situ separation and compaction treatment for metal-containing resist layer

Abstract

Procedure comprehensive: Forming a metal oxide resist layer (40) over a workpiece (10) by: - Performing deposition processes to form metal oxide resist sublayers (40A, 40B, 40C, 40D) over the workpiece (10), each deposition process forming a respective metal oxide resist sublayer (40A, 40B, 40C, 40D) of the metal oxide resist sublayers (40A, 40B, 40C, 40D); and - Performing a compaction process on at least one of the metal oxide resist sublayers (40A, 40B, 40C, 40D), wherein the compaction process increases the density of at least one of the metal oxide resist sublayers (40A, 40B, 40C, 40D), and wherein the compaction process is performed after each deposition cycle, so that each of the metal oxide resist sublayers (40A, 40B, 40C, 40D) is subjected to a respective compaction treatment.

Description

STATE OF THE ART

[0001] Lithography processes are extensively used in the fabrication of integrated circuits (ICs), where various IC structures are transferred onto a workpiece to form an IC device. A lithography process typically involves forming a resist layer over the workpiece, exposing the resist layer with structured radiation, and developing the exposed resist layer, thereby creating a structured resist layer. This structured resist layer is used as a masking element during subsequent IC processing, such as etching, transferring the resist structure from the structured resist layer onto the workpiece. The quality of the resist structure directly impacts the quality of the IC device.As IC technologies continuously evolve to smaller technology nodes (e.g., down to 14 nanometers, 10 nanometers, and below), line edge roughness (LER), line width roughness (LWR), and / or critical dimensional uniformity (CDU) of the resist structure have become critical. Several factors influence the LER, LWR, and / or CDU of the resist structure, including absorption properties (e.g., ability to absorb radiation) and / or outgassing properties (e.g., tendency to release contaminants) of the resist layer. Although existing resist layers and techniques for forming them have generally been suitable for their intended purposes, they have not been entirely satisfactory in all respects, and improvements are needed.

[0002] WO 2019 / 217 749 A1 discloses a process for the fabrication of thin films on semiconductor substrates that can be structured using EUV. The process comprises mixing a vapor stream of an organometallic precursor with a vapor stream of a counter-reactant to form a polymerized metal-organic material and depositing the organometallic polymer-like material onto the surface of the semiconductor substrate.

[0003] US 2018 / 0348636A1 describes a pattern stack for extreme ultraviolet lithography comprising an inorganic hard mask layer, a sublayer on the inorganic hard mask layer, and a resist layer on the sublayer, wherein the inorganic hard mask layer, the sublayer, and the resist layer have a combined thickness in the range of about 8.5 nm to about 70 nm.

[0004] US patent 2017 / 0146909A1 discloses a vacuum-integrated, metal-oxide-containing process for the fabrication of a hard mask. The process combines the steps of film formation by vapor deposition and optical lithography, resulting in the direct photopatterning of metal-oxide-containing hard masks.

[0005] Finally, US 2020 / 0135451A1 describes a method for manufacturing a semiconductor device, comprising forming a first protective layer over a boundary region of a first main surface of a semiconductor substrate and forming a photoresist layer over the first main surface of the semiconductor substrate, removing the first protective layer, and selectively irradiating the photoresist layer with actinic radiation. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The present disclosure is best understood with reference to the following detailed description in conjunction with the accompanying drawings. It should be noted that, in accordance with industry practice, various features are not shown to scale. In fact, the dimensions of the various features may have been arbitrarily enlarged or reduced for the sake of clarity. Fig. Figure 1A illustrates lithography processes that utilize metal oxide resist layers to improve lithography structure accuracy according to various aspects of the present disclosure. Fig. Figure 1B illustrates a cyclic metal resist deposition process for the formation of the metal oxide resist layers of Fig. 1A according to various aspects of the present revelation. Fig. 1C illustrates top views of the metal oxide resist layers of Fig. 1A after separation and structuring according to various aspects of the present disclosure. Fig. 2A illustrates various lithography processes that utilize metal oxide resist layers to improve lithography structure accuracy according to various aspects of the present disclosure. Fig. Figure 2B illustrates a cyclic metal resist deposition process for the formation of the metal oxide resist layers of Fig. 2A according to various aspects of the present revelation. Fig. Figure 3A illustrates different lithography processes that use metal oxide resist layers to improve lithography structure accuracy according to various aspects of the present disclosure. Fig. Figure 3B illustrates a cyclic metal resist deposition process for the formation of the metal oxide resist layers of Fig. 3A according to various aspects of the present revelation. Fig. Figure 4 illustrates a cyclic metal resist deposition process for the formation of a metal oxide resist layer according to various aspects of the present disclosure. Fig. Figure 5 illustrates a cyclic metal resist deposition process for the formation of a metal oxide resist layer according to various aspects of the present disclosure. DETAILED DESCRIPTION

[0007] The present disclosure relates generally to methods for the fabrication of IC (integrated circuit) devices and in particular to lithography techniques and / or lithography materials implemented during the fabrication of IC devices.

[0008] The following disclosure provides many different embodiments, or examples, for implementing various features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on top of a second feature in the following description may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features might not be in direct contact.Additionally, spatially relative expressions, for example, "below," "above," "horizontal," "vertical," "above," "over," "below," "underneath," "upward," "downward," "uppermost," "lowest," etc., as well as derivatives thereof (e.g., "horizontal," "downward," "upward," etc.), may be used to facilitate the present disclosure of the relationship of one feature to another. The spatially relative expressions are intended to cover different orientations of the component exhibiting the features. Furthermore, when a number or range of numbers is described by "essentially," "about," "approximately," and the like, the expression is intended to include numbers that are within a reasonable range, taking into account variations that occur during manufacturing, as a person skilled in the art would understand.For example, the number or range of numbers encompasses a reasonable range that includes the described number, such as within ±10% of the described number, based on known manufacturing tolerances associated with the production of a feature that has a property linked to the number. For example, a material layer with a thickness of "about 5 nm" may encompass a dimensional range of 4.5 nm to 5.5 nm if it is known to those skilled in the art that manufacturing tolerances associated with the deposition of the material layer are ±10%. Furthermore, the present disclosure may repeat reference numbers and / or letters in the various examples. The repetition is for the purpose of simplicity and clarity and does not itself establish a relationship between the various embodiments and / or configurations discussed.

[0009] Lithography processes are used extensively in IC manufacturing, where various IC structures are transferred onto a workpiece to form an IC device. A lithography process involves forming a resist layer over a workpiece and exposing the resist layer with structured radiation. After exposure to the structured radiation, the resist layer is developed in a developer (in other words, a chemical solution). The developer removes portions of the resist layer (for example, exposed portions of positively tinted resist layers or unexposed portions of negatively tinted resist layers), thus forming a structured resist layer.The structured resist layer is then often used as a masking element during a subsequent process, such as etching or implantation, to transfer a structure within the structured resist layer (referred to herein as a resist structure) to the workpiece. Advanced lithography materials, such as chemically enhanced resist materials (CAR materials), have been introduced to improve the sensitivity (S) of the resist layer to radiation, thereby maximizing radiation utilization. Sensitivity generally corresponds to the amount of incident radiation (amount of energy per unit area) required to induce sufficient chemical reactions to define a structure in a resist layer.For example, CAR materials can generate multiple chemical reactions upon exposure to radiation, thereby chemically enhancing one response to the radiation, reducing sensitivity, and thus lowering the exposure doses required to define a resist layer. CAR materials typically contain a polymer that resists an IC process (e.g., an etching process), an acid-generating component (e.g., a photoacid generator (PAG)), and a solvent component. Upon exposure to radiation, the PAG generates acid, which acts as a catalyst to cause chemical reactions that decrease (or increase) the solubility of exposed portions of a resist layer. For example, acid generated by the PAG catalyzes cross-linking of the polymer, thereby reducing the solubility of the exposed portions.

[0010] While CAR materials are configured to reduce sensitivity, they must also meet other resist performance characteristics, such as resolution (R), resist contrast, and roughness. Resolution generally describes a resist material's ability to print (image) a minimum feature size with acceptable quality and / or control, with resist contrast, resist thickness loss, proximity effects, resist expansion and / or contraction (typically caused by development), and / or other resist and / or lithography characteristics contributing to the resolution. Resist contrast generally refers to a resist material's ability to distinguish between light (exposed) and dark (unexposed) areas, with resist materials offering higher contrast providing better resolution, resist profiles, and / or roughness.Roughness, such as line edge roughness (LER) and / or line width roughness (LWR), generally describes whether a structure in a resist layer exhibits edge variations, width variations, variations in critical dimensions, and / or other variations. For example, LER generally describes variations in the edges of a line, whereas LWR generally describes variations in the width of the line, such as from a critical dimensional width (CD width). Improving one resist performance characteristic (e.g., reducing LER) often comes at the cost of worsening another resist performance characteristic (e.g., increasing sensitivity), so attempts to simultaneously minimize resolution, LER, and sensitivity are often referred to as the RLS compromise.Overcoming this RLS compromise presents challenges in meeting lithography process requirements for advanced IC technology nodes, which have continuously smaller feature sizes and therefore increasingly require shrinking resist structure dimensions and finer lithography resolution.

[0011] Extreme ultraviolet lithography (EUV lithography), which utilizes radiation with wavelengths in the EUV range, holds the promise of meeting finer lithography resolution limits, particularly for sub-10 nm IC fabrication. However, CAR materials with higher sensitivity at EUV wavelengths are often required because exposure doses needed to meet resolution, contrast, and / or LER requirements, along with throughput requirements (such as wafers per hour (WPH)), are limited by conventional EUV sources. For example, since the number of photons absorbed by a volume of resist material is proportional to the wavelength, and the amount of absorbed energy is proportional to the exposure dose, the total absorbed energy is discretized into fewer photons as the wavelength decreases.A volume of resist material therefore absorbs fewer EUV photons than DUV photons when exposed to the same exposure dose, which often means that less acid is generated by CAR materials for catalyzing reactions. This phenomenon is generally referred to as shot noise. Therefore, increasing the EUV exposure dose can mitigate shot noise, thereby improving resolution, contrast, and / or roughness. This can be achieved by increasing the EUV source power or decreasing the scanning rate (in other words, decreasing throughput, such as WPH).Since current EUV sources have limited capability to meet the high-performance EUV source requirements for CAR materials, and reduced throughput is not a viable option to meet next-generation IC manufacturing requirements, metal oxide resist materials that exhibit sufficient sensitivity to radiation while still fulfilling other RLS characteristics, such as resolution and LER, are being explored as a potential replacement for CAR materials in EUV lithography.

[0012] Metal oxide resist materials have been observed to exhibit better EUV absorption characteristics (e.g., metal oxide resist materials can absorb more EUV photons than CAR materials), better LER / LWR characteristics (e.g., metal oxide resist materials are often less susceptible to secondary electron exposure and / or acid enhancement effects that cause resist haze in CAR materials), and better etching characteristics than CAR materials (e.g., metal oxide resist materials achieve greater etch selectivity when used as an etching mask compared to CAR materials). The present disclosure explores deposition techniques to further improve the structuring characteristics of metal oxide resist materials.For example, the present disclosure recognizes that metal oxide resist materials formed by conventional deposition techniques exhibit random, loose, and often disordered, non-dense, and / or non-uniform atomic structures, which can impair LER / LWR and structural uniformity. Furthermore, such atomic structures can lead to undesirable outgassing, which can contaminate workpieces processed using the metal oxide resist materials and / or process tools used to process the metal oxide resist materials (e.g., depositing, exposure, developing, etc.). The present disclosure therefore discloses methods for forming metal oxide resist materials with atomic structures that are less random, loose, and ordered, denser, and / or more uniform than metal oxide resist materials formed using conventional deposition techniques.The disclosed methods comprise performing a cyclic deposition process to form metal oxide resist sublayers that combine to form a metal oxide resist layer, and performing a densification process that increases the density of at least one of the metal oxide resist sublayers. The deposition and densification processes can be performed in the same process chamber (i.e., in-situ). Parameters of the deposition and / or densification processes are adjusted to achieve uniform or different densities in the metal oxide resist sublayers, thereby providing different density profiles. In some embodiments, a densification process is performed prior to the deposition process, for example, to improve the adhesion of the metal oxide resist layer to a workpiece.Metal oxide resist layers formed as described herein can reduce outgassing, improve LER / LWR, and / or enhance structuring uniformity across a wafer. Different embodiments disclosed herein offer different advantages, and no particular advantage is necessarily required in all embodiments.

[0013] With regard to Fig. 1A - 1C, illustrated Fig. 1A Lithography processes, such as lithography process A and lithography process B, which utilize metal oxide resist layers to improve lithography structure accuracy according to various aspects of the present disclosure, are illustrated. Fig. 1B a cyclic metal resist deposition process A used to form the metal oxide resist layer in lithography process B according to various aspects of the present disclosure and illustrates Fig. 1C Top views of workpieces after deposition and structuring of the metal oxide resist layers used in lithography process A and lithography process B, according to various aspects of the present disclosure. Fig. 1A - 1C depicts a workpiece 10, in whole or in part, at an intermediate manufacturing stage of an IC component, where workpiece 10 is undergoing lithography process A or lithography process B. In some embodiments, the IC component is a microprocessor, a memory, and / or another IC component, or a section thereof. Workpiece 10 may be a section of an IC chip, a system-on-a-chip (SoC), or a section thereof, comprising various passive and active microelectronic components, such as resistors, capacitors, inductors, diodes, p-type field-effect transistors, n-type field-effect transistors, metal-oxide-semiconductor field-effect transistors, complementary metal-oxide-semiconductor transistors, bipolar transistors, side-diffused metal-oxide-semiconductor transistors, high-voltage transistors, high-frequency transistors, fin-type field-effect transistors, gate-all-around transistors, other suitable IC components, or combinations thereof. Fig. Figures 1A-1C have been simplified for clarity to better understand the inventive concepts of the present disclosure. Additional features may be added to workpiece 10, lithography process A, lithography process B and / or cyclic metal resist deposition process A, and some of the features described below may be replaced, modified, or eliminated in other embodiments of workpiece 10, lithography process A, lithography process B, and / or cyclic metal resist deposition process A.

[0014] in Fig. In 1A-1C, workpiece 10 comprises a wafer 15 and a metal layer 20, which is to be processed (hereinafter also referred to as a substrate layer), arranged over wafer 15. Wafer 15 comprises a substrate (for example, a semiconductor substrate), a mask (also referred to as a photomask or filament mesh), or any base material on which processing can be implemented to provide material layers to form various features of an IC device.Depending on the IC fabrication stage, wafer 15 has various material layers (for example, dielectric layers, semiconductor layers, and / or metal layers) configured to form IC features (for example, n-wells, p-wells, insulation structures (for example, trench insulation structures and / or deep trench insulation structures), source / drain features (having epitaxial source / drain features), metal gates and / or dummy gates, gate spacers, source / drain contacts, gate contacts, vias, metal traces, other IC features, or combinations thereof). In some embodiments, material layer 20 is a semiconductor layer containing, for example, silicon, germanium, silicon-germanium, other suitable semiconductor components, or combinations thereof.In some embodiments, metal layer 20 is a semiconductor layer containing, for example, titanium, aluminum, tungsten, tantalum, copper, cobalt, ruthenium, alloys thereof, other suitable metal components and / or alloys thereof, or combinations thereof. In some embodiments, material layer 20 is a dielectric layer containing, for example, silicon, metal, oxygen, nitrogen, carbon, other suitable dielectric components, or combinations thereof. In some embodiments, material layer 20 is a hard mask layer that is to be structured for use in subsequent processing of workpiece 10. In some embodiments, material layer 20 is an antireflective coating layer (ARC layer).In some embodiments, material layer 20 is a layer to be used to form a gate feature, such as a gate dielectric and / or a gate electrode, a source / drain feature, such as an epitaxial source / drain, and / or an interconnect feature, such as a conductive structure or a dielectric layer of a multilayer interconnect, of workpiece 10. In some embodiments where workpiece 10 is fabricated into a mask for structuring IC devices, wafer 15 is a mask substrate containing a transparent material and / or a thermally expanding material (e.g., glass, quartz, silicon dioxide titanium, and / or another suitable material), and material layer 20 is a layer to be processed to form an IC structure within it, such as an absorber layer (for example, material layer 20 contains chromium).The present disclosure considers embodiments in which material 20 of workpiece 10 is omitted and wafer 15 is processed directly, and embodiments in which material layer 20 has more than one material layer.

[0015] Both lithography process A and lithography process B begin with the deposition of a metal oxide resist layer having a target thickness T over material layer 20, such as a metal oxide resist layer 30 in lithography process A and a metal oxide resist layer 40 in lithography process B. Both metal oxide resist layer 30 and metal oxide resist layer 40 are sensitive to radiation used during a lithography exposure process, such as deep ultraviolet (DUV) radiation, EUV radiation, electron beam radiation, ion beam radiation, and / or other suitable radiation. In some embodiments, both metal oxide resist layer 30 and metal oxide resist layer 40 are sensitive to radiation with a wavelength shorter than approximately 13.5 nm.Metal oxide resist layer 30 and metal oxide resist layer 40 each contain a metal- and oxygen-containing radiation-sensitive material, wherein the metal is hafnium, titanium, zirconium, tantalum, tin, lanthanum, indium, antimony, another metal component, facilitates radiation absorption (e.g., EUV radiation) and / or resistance to an IC process used during the manufacture of workpiece 10 (e.g., etching), or combinations thereof. In some embodiments, metal oxide resist layer 30 and / or metal oxide resist layer 40 may include other resist components that facilitate radiation absorption and / or cross-linking reactions upon radiation exposure, such as a photoacid generator component (PAG component), a thermal acid generator component (TAG component), a photodegradable base component (PDB component), other suitable resist components, or combinations thereof.In some embodiments, an arc reaction (ARC) layer is formed over material layer 20 prior to the deposition of metal oxide resist layer 30 and / or metal oxide resist layer 40, such that the metal oxide resist layer 30 and / or metal oxide resist layer 40 are deposited on the ARC layer. The ARC layer can be a nitrogen-free arc reaction (NFARC) layer containing silicon oxide, silicon oxycarbide, other suitable materials, or combinations thereof. In some embodiments, more than one layer (comprising one or more ARC layers) can be formed between material layer 20 and the metal oxide resist layer 30 and / or metal oxide resist layer 40. The metal oxide resist layer 30 and / or metal oxide resist layer 40 are also referred to as metal resist layers, photosensitive metal layers, metal imaging layers, metal structuring layers, and / or radiation-sensitive metal layers.

[0016] Metal oxide resist layer 30 and metal oxide resist layer 40 are formed by different deposition processes, resulting in different characteristics that affect structural accuracy. In lithography process A, metal oxide resist layer 30 is deposited over material layer 20 by a chemical vapor deposition (CVD) process. In some embodiments, the CVD process includes loading workpiece 10, which has material layer 20 arranged over wafer 15, into a process chamber and heating workpiece 10 to a desired temperature (e.g.,a temperature that facilitates the chemical reactions required to form metal-and-oxygen resist material over material layer 20), the flow of one or more precursors and / or carriers into the process chamber, whereby the precursors react and / or decompose to form a metal-and-oxygen resist material over material layer 20, and the removal of any remaining precursors (e.g., unreacted precursors), carriers, and / or byproducts from the process chamber. The metal-and-oxygen resist material accumulates on material layer 20, and the CVD process is carried out until the metal-and-oxygen resist material that has accumulated over material layer 20 has a target thickness T.During the CVD process, the precursors can react with each other, with material layer 20, with metal-and-oxygen-containing resist material collected on material layer 20, and / or with byproducts of chemical reactions thereof to form metal oxide resist layer 30. In some embodiments, the CVD process is a plasma-enhanced CVD (PECVD), a distant PECVD process (RPECVD process), a metal-organic CVD process (MOCVD process), a low-pressure CVD process (SACVD process), an ultra-high vacuum CVD process (UHVCVD process), a sub-atmospheric pressure CVD process (SACVD process), a laser-assisted CVD process (LACVD process), an aerosol-assisted CVD process (AACVD process), an atomic layer CVD (ALCVD), another suitable CVD process, or combinations thereof.In some embodiments, a metal oxide resist layer 30, having thickness T, is deposited over material layer 20 by an atomic layer deposition (ALD) process, a physical vapor deposition (PVD) process, or another suitable deposition process.

[0017] Because chemical reactions during the CVD process are random and / or incomplete, it has been observed that metal oxide resist layer 30 can exhibit a random, loose, and often disordered, non-dense, and / or non-uniform atomic structure, which can reduce structuring uniformity. For example, the atomic structure of metal oxide resist layer 30 shows randomly stacked, loosely packed metal atoms, oxygen atoms, and single metal oxide molecules (Me1O). x , where x is a number of oxygen atoms) and / or metal oxide clusters (Me y O z, where y is a number of metal atoms and z is a number of oxygen atoms) which can be collectively referred to as metal-oxygen components MeO. Metal-oxygen components MeO may not have an ordered arrangement (e.g., a repeating structure of metal-oxygen components MeO), which can result in metal oxide resist layer 30 having unequal clusters of metal-oxygen components MeO and therefore a non-uniform density (e.g., the amount of metal-oxygen components MeO in one section of metal oxide resist layer 30 differs from the amount of metal-oxygen components MeO in another, similarly sized section of metal oxide resist layer 30).Since the amount of radiation a material can absorb depends on its density, and metal oxide resist layer 30 has a non-uniform density, metal oxide resist layer 30 cannot absorb radiation uniformly, which reduces LER / LWR that can be achieved by structuring metal oxide resist layer 30 (e.g., structured metal oxide resist layer 30 exhibits larger than desired LER / LWR and deteriorated line width and / or line edge uniformity), and / or requires larger exposure doses to ensure sufficient and / or uniform absorption of radiation to improve LER / LWR.Furthermore, the random arrangement of metal and oxygen components MeO can lead to gaps and / or reactions (V) that form within the atomic structure of metal oxide resist layer 30, and incomplete chemical reactions during the CVD process can lead to metal and oxygen components MeO that are not connected (bound) to any other metal and oxygen components MeO of metal oxide resist layer 30, as in . Fig. Figure 1A illustrates this. These “loose” metal and oxygen components MeO and / or weakly bound metal and oxygen components MeO can outgas during subsequent processing (i.e., escape from metal oxide resist layer 30 into the process chamber environment), which can contaminate workpiece 10 and / or the process chamber. Outgassed metal and oxygen components MeO can cause film defects, for example, by scraping and / or peeling off metal oxide resist layer 30, material layer 20, and / or wafer 15. Furthermore, if multiple wafers are processed to form metal oxide resist layers, such as metal oxide resist layer 30, in a process chamber, structural accuracy deteriorates over time as outgassing contamination accumulates in the process chamber.

[0018] To address such problems, the present disclosure proposes cyclic metal oxide resist deposition processes that provide metal oxide resist layers that are denser than metal oxide resist layer 30 and absorb radiation better, thus enabling the implementation of lower exposure doses to structure the metal oxide resist layers while still achieving uniform radiation absorption to improve LER / LWR. The denser metal oxide resist layers also exhibit less outgassing than metal oxide resist layer 30. In some embodiments, atomic structures of metal oxide resist layers formed by the proposed cyclic metal oxide resist deposition processes have metal and oxygen components stacked in an ordered arrangement (e.g., a repeating structure of metal and oxygen components).In some embodiments, atomic structures of metal oxide resist layers formed by the proposed cyclic metal oxide resist deposition processes exhibit fewer gaps and / or incomplete metal-oxygen bonds (and in some embodiments are essentially free of gaps and / or incomplete metal-oxygen bonds) compared to metal oxide resist layer 30. In some embodiments, clusters of metal-oxygen constituents are uniformly distributed in metal oxide resist layers formed by the proposed cyclic metal oxide resist deposition processes, such that metal oxide resist layers formed by the proposed cyclic metal oxide resist deposition processes exhibit essentially uniform densities (e.g., amounts of metal-oxygen constituents in different, similarly sized sections of the metal oxide resist layers are essentially the same).In some embodiments, the concentration of metal oxide clusters, the metal concentration, the oxygen concentration, and / or the metal oxide concentration in the proposed metal oxide resist layers increases or decreases from the top surfaces to the bottom surfaces of the metal oxide resist layers to achieve graded density characteristics (e.g., a density that increases or decreases from the top surfaces to the bottom surfaces of the metal oxide resist layers). In some embodiments, the concentration of metal oxide clusters, the metal concentration, the oxygen concentration, and / or the metal oxide concentration in the proposed metal oxide resist layers differs at different depths to achieve desired density characteristics, such as those described herein. In some embodiments, the proposed metal oxide resist layers may contain 12-MeO. x -Cluster, 8-MeO x -Cluster, 6-MeO x-Cluster, 4-MeO x -Cluster, Dimer-MeO x -Cluster and / or Mono-MeO x -Exhibit clusters, depending on desired density characteristics, such as those described herein.

[0019] With regard to lithography process B, a cyclic metal resist deposition process A forms a metal oxide resist layer 40 with a substantially uniform density from bottom to top, as from a bottom surface of metal oxide resist layer 40 (e.g., adjacent to material layer 20) to a top surface of metal oxide resist layer 40. The density of metal oxide resist layer 40 is greater than the density of metal oxide resist layer 30, so that metal oxide resist layer 40 can absorb more radiation than metal oxide resist layer 30 when exposed with the same radiation dose, and can absorb such radiation more uniformly than metal oxide resist layer 30. For example, cyclic metal resist deposition process A forms a metal oxide resist sublayer 40A, a metal oxide resist sublayer 40B, a metal oxide resist sublayer 40C and a metal oxide resist sublayer 40D, which together form a metal oxide resist layer 40 with thickness T.Metal oxide resist sublayers 40A–40D each have a thickness t1, a thickness t2, a thickness t3, and a thickness t4, where the sum of thicknesses t1, t2, t3, and t4 equals the target thickness T. The density of metal oxide resist sublayer 40A, the density of metal oxide resist sublayer 40B, the density of metal oxide resist sublayer 40C, and the density of metal oxide resist sublayer 40D are essentially the same. In the illustrated embodiment, the densities of metal oxide resist sublayers 40A–40D are all greater than the density of metal oxide resist layer 30. In the illustrated embodiment, thicknesses t1, t2, t3, and t4 are essentially the same. In some embodiments, thickness t1, thickness t2, thickness t3 and / or thickness t4 are different or the same, depending on the desired density profile and / or density characteristics.

[0020] With regard to Fig. 1B comprises cyclic metal resist deposition process A comprising four cycles, each cycle forming one of metal oxide resist sublayers 40A-40D, and each cycle comprising a deposition process and a densification process according to the invention. For example, cyclic metal resist deposition process A comprises cycle 1, cycle 2, cycle 3, and cycle 4 (alternatively referred to as phases 1-4). Cycle 1 comprises performing a deposition process 50-1 to form a metal oxide resist sublayer 40A' with thickness t1 and a first density on material layer 20, and performing a densification process 52-1 on metal oxide resist sublayer 40A', thereby forming metal oxide resist sublayer 40A with a second density greater than the first density.Cycle 2 comprises performing a deposition process 50-2 to form a metal oxide resist sublayer 40B' with thickness t2 and a third density on metal oxide resist sublayer 40A, and performing a compaction process 52-2 on metal oxide resist sublayer 40B', thereby forming metal oxide resist sublayer 40B with a fourth density, greater than the third density. Cycle 3 comprises performing a deposition process 50-3 to form a metal oxide resist sublayer 40C' with thickness t3 and a fifth density on metal oxide resist sublayer 40B, and performing a compaction process 52-3 on metal oxide resist sublayer 40C', thereby forming metal oxide resist sublayer 40C with a sixth density, greater than the fifth density.Cycle 4 comprises performing a deposition process 50-4 to form a metal oxide resist sublayer 40D' of thickness t4 and a seventh density of metal oxide resist sublayer 40C, and performing a compaction process 52-4 on metal oxide resist sublayer 40D', thereby forming metal oxide resist sublayer 40D with an eighth density greater than the seventh density. In the illustrated embodiment, the second, fourth, sixth, and eighth densities (i.e., densities after compaction processes 52-1 - 52-4) are essentially the same, such that the metal oxide resist layer 40 has an essentially uniform density from bottom to top. In some embodiments, the first, third, fifth, and seventh densities (i.e., densities of metal-and-oxygen-containing resist materials as deposited) are essentially the same.In some embodiments, the first density, the third density, the fifth density, and / or the seventh density are the same as a density of metal oxide resist layer 30. In some embodiments, the first density, the third density, the fifth density, and / or the seventh density are different. In some embodiments, compaction processes can reduce thickness t1, thickness t2, thickness t3, and / or thickness t4, such that the thicknesses t1–t4 of the metal oxide resist sublayers 40A'–40D' as deposited are each greater than the respective thicknesses t1–t4 of the metal oxide resist sublayers 40A–40D.

[0021] In some embodiments, the deposition processes are 50-1 - 50-4 CVD processes. In some embodiments, the deposition processes are 50-1 - 50-4 ALD processes. After loading workpiece 10, which has material layer 20 arranged over wafer 15, into a process chamber, each of the deposition processes 50-1 - 50-4 can include heating workpiece 10 to a desired temperature (e.g. a temperature that facilitates chemical reactions required to form metal-and-oxygen-containing resist material over material layer 20), flowing one or more deposition precursors and / or support materials into the process chamber, the deposition precursors reacting and / or decomposing to form a metal-and-oxygen-containing resist material over material layer 20, and cleaning up any remaining deposition precursors (e.g. unreacted deposition precursors), support materials, and / or by-products from the process chamber.Each of the deposition processes 50-1 - 50-4 comprises at least one deposition phase and at least one cleaning phase. The metal-oxygen-containing resist material accumulates on material layer 20 during the deposition phase, and the deposition phase is carried out until the metal-oxygen-containing resist material accumulating on material layer 20 has a thickness t1, thickness t2, thickness t3, or thickness t4, depending on the number of cycles. During the deposition phase, the deposition precursors can react with each other, with material layer 20, with metal-oxygen-containing resist material accumulating on material layer 20, and / or with byproducts of chemical reactions thereof to form metal oxide resist sublayers 40A - 40D. In some embodiments, the deposition precursors comprise a metal-containing precursor, a reaction gas, and / or a support. In some embodiments, the metal-containing precursor contains M. aR b X c, where 1 ≤ a ≤ 2, b ≥ 1, and c ≥ 1. In some embodiments, b + c ≤ 5. In some embodiments, M is Sn, Bi, Sb, In, Te, Ti, Zr, Hf, V, Co, Mo, W, Al, Ga, Si, Ge, P, As, Y, La, Ce, or Lu. In some embodiments, R is a substituted alkyl group, a substituted alkenyl group, a substituted carboxylate group, an unsubstituted alkyl group, an unsubstituted alkenyl group, or an unsubstituted carboxylate group. In some embodiments, X is a halide group or a sulfonate group. In some embodiments, the reaction gas contains amine, water, ozone, hydrogen peroxide, other suitable reaction gas components, or combinations thereof. In some embodiments, the carrier gas contains argon (e.g., Ar), helium (e.g., He), nitrogen (e.g., N₂), other suitable carrier gas components, or combinations thereof. In some embodiments, the flow rate of a deposition precursor is approximately 10 sccm to approximately 1,000 sccm.In some embodiments, the flow rate of a support material is approximately 100 sccm to approximately 10,000 sccm. In some embodiments, power is applied to a deposition precursor to generate a plasma, such as a power of approximately 10 W to approximately 1,000 W. In some embodiments, the plasma is generated by a radio frequency power source (RF power source), so the power is RF power. In some embodiments, the duration of the deposition phase is approximately 3 seconds to approximately 3,600 seconds. In some embodiments, the pressure maintained in the process chamber during the deposition phase is approximately 13 Pascals to approximately 19,998 Pascals. In some embodiments, the temperature maintained in the deposition phase during the deposition phase is approximately 25 °C to approximately 300 °C. In some embodiments, the cleaning phase may include the removal of an inert gas (e.g.,an argon-containing gas, a helium-containing gas, another suitable inert gas, or combinations thereof) to flow into the process chamber. In some embodiments, the flow rate of the inert gas is approximately 100 sccm to approximately 10,000 sccm. In some embodiments, the duration of the cleaning phase is approximately 3 seconds to approximately 1,000 seconds. In some embodiments, the pressure maintained in the process chamber during the cleaning phase is approximately 1333 Pascals to approximately 101325 Pascals. In some embodiments, the temperature maintained in the process chamber during the cleaning phase is approximately 25 °C to approximately 300 °C. In some embodiments, deposition processes 50-1 - 50-4 are the same. In some embodiments, deposition processes 50-1 - 50-4 are different.In some embodiments, deposition processes 50-1 - 50-4 are any combination of deposition processes to achieve the desired density profile and / or density characteristics of the metal oxide resist layer 40.

[0022] Compaction processes 52-1 - 52-4 comprise a treatment phase in which workpiece 10 undergoes a treatment capable of compacting (i.e., increasing the density of) metal-and-oxygen-containing resist materials, and a cleaning phase. In some embodiments, the treatment modifies the atomic structure of the metal-and-oxygen-containing resist materials such that the atomic structure is more ordered and / or more tightly packed after the treatment. For example, the treatment rearranges metal atoms and / or oxygen atoms of the metal-and-oxygen-containing resist materials such that the metal-and-oxygen-containing resist materials exhibit an ordered arrangement of metal atoms and / or oxygen atoms after the treatment and / or have less spacing between metal atoms and / or oxygen atoms after the treatment.In some embodiments, the treatment strengthens metal-oxygen bonding and / or increases the uniformity of metal-oxygen bonding in metal-oxygen-containing resist materials. For example, the treatment induces chemical reactions such that partially reacted components of metal-oxygen-containing resist materials are fully reacted after treatment, and / or unreacted components of metal-oxygen-containing resist materials are partially or fully reacted in the process chamber after treatment. In some embodiments, the treatment induces partial cross-linking in the metal-oxygen-containing resist materials, which can increase the density of metal-oxygen-containing resist materials. The cleaning phase removes (rinses) any remaining precursors (e.g.,Unreacted deposition precursors, unreacted treatment precursors, "loosely" reacted precursors, "loose" metal and oxygen components, and / or other "loosely" reacted components), carrier materials, and / or byproducts from the process chamber, which reduces outgassing from metal oxide resist layer 40 and contamination of workpiece 10 and / or the resulting process chamber compared to metal oxide resist layer 30. In some embodiments, the cleaning phase includes the introduction of an inert gas (e.g., an argon-containing gas, a helium-containing gas, another suitable inert gas, or combinations thereof) into the process chamber. In some embodiments, the inert gas flow rate is approximately 100 sccm to approximately 10,000 sccm. In some embodiments, the duration of the cleaning phase is approximately 3 seconds to approximately 600 seconds.In some embodiments, the pressure maintained in the process chamber during the cleaning phase is approximately 1333 Pascals to approximately 101325 Pascals. In some embodiments, the temperature maintained in the process chamber during the cleaning phase is approximately 25 °C to approximately 300 °C.

[0023] Example treatments that can increase the density of metal-and-oxygen-containing resist materials and / or achieve modifications of the metal-and-oxygen-containing resist materials as described herein include a plasma compaction process, a softbake process, a UV irradiation process, an infrared irradiation process (IR irradiation process), another suitable compaction process, or combinations thereof. In some embodiments, compaction processes 52-1–52-4 are the same treatment types (e.g., compaction processes 52-1–52-4 are all plasma compaction processes). In other embodiments, compaction processes 52-1–52-4 are different treatment types (e.g., compaction processes 52-1 and 52-4 are plasma compaction processes, while compaction processes 52-1 and 52-3 are softbake processes).In some embodiments, compaction processes 52-1 - 52-4 are any combination of compaction treatments to achieve the desired density profile and / or desired density characteristics of metal oxide resist layer 40.

[0024] In some embodiments, a plasma compaction process comprises flowing one or more compaction precursors and / or carriers into the process chamber, generating a plasma from the compaction precursors, and irradiating a metal oxide resist sublayer with the plasma (e.g., bombarding the metal oxide resist sublayer with the plasma). In some embodiments, the compaction precursors comprise a metal-containing precursor, a reaction gas, and / or a carrier. In some embodiments, the metal-containing precursor M a R b X c, where 1 ≤ a ≤ 2, b ≥ 1, and c ≥ 1. In some embodiments, b + c ≤ 5. In some embodiments, M is Sn, Bi, Sb, In, Te, Ti, Zr, Hf, V, Co, Mo, W, Al, Ga, Si, Ge, P, As, Y, La, Ce, or Lu. In some embodiments, R is a substituted alkyl group, a substituted alkenyl group, a substituted carboxylate group, an unsubstituted alkyl group, an unsubstituted alkenyl group, or an unsubstituted carboxylate group. In some embodiments, X is a halide group or a sulfonate group. In some embodiments, the reaction gas contains amine, water, ozone, hydrogen peroxide, another suitable reaction gas, or combinations thereof. In some embodiments, a carrier gas contains argon (e.g., Ar), helium (e.g., He), nitrogen (e.g., N₂), other suitable carrier gas components, or combinations thereof. In some embodiments, the flow rate of a compression precursor is approximately 10 sccm to approximately 1,000 sccm.In some embodiments, the flow rate of a carrier material is approximately 100 sccm to approximately 10,000 sccm. In some embodiments, the power applied to a compaction precursor and / or a carrier material to generate the plasma is approximately 10 W to approximately 1,000 W. In some embodiments, the power applied to the compaction precursor and / or the carrier material to generate the plasma is lower, such as less than approximately 100 W. In some embodiments, the plasma is generated by an RF power source, so the power is RF power. In some embodiments, the metal oxide resist sublayer is exposed to the plasma for approximately 3 seconds to approximately 3,600 seconds. In some embodiments, the pressure maintained in the process chamber during the plasma compaction process is approximately 13 Pascals to approximately 19,998 Pascals.In some embodiments, the temperature maintained in the process chamber during the plasma compression process is approximately 25 °C to approximately 300 °C.

[0025] In some embodiments, a softbake process (also referred to as a tempering process and / or a heating process) heats workpiece 10 (which has one or more metal oxide resist sublayers) for a period of time. The softbake process can apply heat to a front face of workpiece 10 (e.g., to a top metal oxide resist sublayer of workpiece 10), a bottom of workpiece 10 (e.g., to wafer 15), sides of workpiece 10, or combinations thereof. In some embodiments, the softbake process heats workpiece 10 to a temperature of about 80 °C to about 250 °C. In some embodiments, workpiece 10 is baked (tempered) for about 60 seconds to about 300 seconds. In some embodiments, a pressure maintained in the process chamber during the softbake process is about 13 Pascals to about 19,998 Pascals.In some embodiments, workpiece 10 is baked (tempered) in an inert gas environment (which, for example, contains argon, helium and / or other inert gas components) or a reactive gas environment (which, for example, contains oxygen, hydrogen, nitrogen and / or other reactive gas components).

[0026] In some embodiments, a UV radiation process exposes one or more metal oxide resist sublayers of workpiece 10 to UV radiation for a specific period of time. In some embodiments, the UV radiation has a wavelength of approximately 10 nm to approximately 400 nm. In some embodiments, the metal oxide resist sublayer is exposed to UV radiation for approximately 60 seconds to approximately 3,600 seconds. In some embodiments, the UV radiation process heats workpiece 10 to a temperature of approximately 20 °C to approximately 25 °C. In some embodiments, the pressure maintained in the process chamber during the UV radiation process is approximately 0.0013 Pascals to approximately 0.013 Pascals.In some embodiments, workpiece 10 is treated with UV radiation in an inert gas environment (which, for example, contains argon, helium and / or other inert gas components) or a reactive gas environment (which, for example, contains oxygen, hydrogen, nitrogen and / or other reactive gas components).

[0027] In some embodiments, an infrared radiation process (IR radiation process) exposes one or more metal oxide resist sublayers of workpiece 10 to IR radiation for a specified period. In some embodiments, the IR radiation has a wavelength greater than approximately 300 nm. In some embodiments, the IR radiation is far-infrared radiation (FIR radiation), which has a wavelength of, for example, approximately 50 µm to approximately 1,000 µm. In some embodiments, the metal oxide is exposed to IR radiation for approximately 10 seconds to approximately 600 seconds. In some embodiments, the IR radiation process heats workpiece 10 to a temperature of approximately 25 °C to approximately 250 °C. In some embodiments, the pressure maintained in the process chamber during the IR radiation process is approximately 13 Pascals to approximately 19,998 Pascals.In some embodiments, workpiece 10 is treated with IR radiation in an inert gas environment (which, for example, contains argon, helium and / or other inert gas components) or a reactive gas environment (which, for example, contains oxygen, hydrogen, nitrogen and / or other reactive gas components).

[0028] In some embodiments, a pre-deposition treatment process is performed before deposition processes 50-1 - 50-4 to improve adhesion of the metal oxide resist layer 40 to the material layer 20 and to reduce detachment of the metal oxide resist layer 40 from the material layer 20. In some embodiments, the pre-deposition treatment process is combined with deposition process 50-1. For example, a deposition phase may comprise a pre-deposition section and a deposition section, with deposition parameters being adjusted during deposition process 50-1 to transition from the pre-deposition section to the deposition section, such as deposition precursor flow rate, power, time, and / or temperature.The deposition parameters of the pre-deposition section can be adjusted to enhance chemical reactions (and thus crosslinking and / or bonding) between the deposition precursor and the material layer 20 to form a metal-and-oxygen seed material on the material layer 20. The deposition parameters of the deposition section can be adjusted to form metal-and-oxygen-containing material exhibiting density characteristics desired for the metal oxide resist sublayer 40A. In such embodiments, the metal-and-oxygen-containing seed material can form a section of the metal oxide resist sublayer 40A. In some embodiments, the pre-deposition treatment process is a plasma treatment process. The present disclosure considers a pre-deposition treatment process comprising any treatment that can be performed on workpiece 10 to enhance the adhesion of the metal oxide resist layer 40 to it.

[0029] Deposition processes 50-1 - 50-4 and compaction processes 52-1 - 52-4 are performed in-situ. As used herein, the term "in-situ" is used to describe processes that are performed while a workpiece remains within a processing system (e.g., a CVD tool) and where, for example, the processing system allows the workpiece to remain under vacuum conditions. Therefore, the term "in-situ" can also refer more generally to processes in which the workpiece being processed is not exposed to an external environment (e.g., outside the processing system). Subsequent processing, such as exposure and development, may be performed ex-situ (i.e., workpiece 10 is transferred from a CVD tool to an exposure and / or development tool).In the illustrated embodiment, deposition processes 50-1 - 50-4 and compaction processes 52-1 - 52-4 are carried out in the same process chamber of the processing system as a process chamber of a CVD tool. In some embodiments, deposition processes 50-1 - 50-4 are carried out in a first process chamber of a multi-chamber processing system, compaction processes 52-1 - 52-4 are carried out in a second process chamber of the multi-chamber processing system, and the workpiece 10 is not exposed to any external environment and remains under vacuum while it is transferred between the first and second process chambers and within the multi-chamber IC processing system 100 to form the metal oxide resist layer 40.

[0030] Back to Fig. 1A, after deposition of metal oxide resist layer 30 and metal oxide resist layer 40, lithography process A and lithography process B proceed with exposure processes that expose the metal oxide resist layer 30 and metal oxide resist layer 40 with structured radiation. In some embodiments, the structured radiation has a wavelength shorter than approximately 250 nm, such as DUV radiation, EUV radiation, and / or other suitable radiation. In the illustrated embodiment, the structured radiation is EUV radiation, such as radiation having a wavelength shorter than approximately 13.5 nm. In some embodiments, as illustrated, a mask 60, which has an IC structure defined therein, is used to provide structured radiation that can form an image of the IC structure on the metal oxide resist layer 30 and metal oxide resist layer 40.Mask 60 blocks, allows, and / or reflects radiation to metal oxide resist layer 30 and metal oxide resist layer 40, depending on the mask structure of mask 60 and / or the mask type (for example, binary mask, phase-shift mask, or EUV mask). The exposure process can be carried out in air, liquid (immersion lithography), or vacuum (for example, when workpiece 10 is exposed with EUV radiation and / or an electron beam). In some embodiments, the exposure process modulates radiation, such as an electron beam (e-beam) or an ion beam, directly according to an IC structure, without using a mask such as mask 60.

[0031] Since metal oxide resist layer 30 and metal oxide resist layer 40 are sensitive to radiation, latent structures are formed on these layers during the exposure processes. A latent structure generally refers to a structure exposed on a resist layer that becomes a physical resist structure after the resist layer has undergone a development process. Fig. 1A has the latent structure of metal oxide resist layer 30 with exposed sections 30E and unexposed sections 30U, and the latent structure of metal oxide resist layer 40 has exposed sections 40E and unexposed sections 40U. Exposed sections 30E, 40E change physically and / or chemically in response to the exposure process. In the illustrated embodiment, the exposure process causes chemical reactions in exposed sections 30E, 40E that decrease the solubility of exposed sections 30E, 40E in a developer. In some embodiments, exposed sections 30E, 40E are insoluble in the developer. In some embodiments, a post-exposure baking (PEB) process is performed on metal oxide resist layer 30 and / or metal oxide resist layer 40 after the exposure processes.The PEB process raises the temperature of metal oxide resist layer 30 and / or metal oxide resist layer 40 to approximately 90 °C to approximately 250 °C. This is because metal oxide resist layer 40 has a dense and uniform atomic structure, while metal oxide resist layer 30 has a loose and random atomic structure (see, for example, top views of metal oxide resist layer 30 and metal oxide resist layer 40 after deposition in [location missing]). Fig. 1C), the exposure dose of structured radiation projected onto metal oxide resist layer 40 can be lower than the exposure dose of structured radiation projected onto metal oxide resist layer 30. In some embodiments, the exposure dose of structured radiation projected onto metal oxide resist layer 40 can be approximately 0.1 times lower than the exposure dose of structured radiation projected onto metal oxide resist layer 30.Furthermore, in contrast to metal oxide resist layer 30, metal oxide resist layer 40 exhibits no (or minimal) outgassing during the exposure process, the PEB process and / or other subsequent processes, thereby reducing (and in some embodiments preventing) film defects on workpieces caused by outgassing contamination and / or limiting (and in some embodiments preventing) reductions in structural accuracy over time caused by outgassing contamination that accumulates within a process chamber when workpieces are processed to form metal oxide layers.

[0032] Lithography process A and lithography process B then each proceed to perform a development process on metal oxide resist layer 30 and metal oxide resist layer 40, respectively, forming a structured metal oxide resist layer 30' and a structured metal oxide resist layer 40'. The development processes dissolve exposed (or unexposed) sections of metal oxide resist layer 30 and metal oxide resist layer 40 depending on the characteristics of metal oxide resist layer 30 and metal oxide resist layer 40, respectively, and the characteristics of a developing solution used in the development process. In the illustrated embodiment, negative tinting (NTD) development processes are performed to remove unexposed sections 30U of metal oxide resist layer 30 and unexposed sections 40U of metal oxide resist layer 40.For example, NTD developers are applied to metal oxide resist layer 30 and metal oxide resist layer 40, resolving unexposed sections 30U and 40U, leaving structured metal oxide resist layer 30', which has apertures 62 defined by exposed sections 30E, and structured metal oxide resist layer 30', which has apertures 64 defined by exposed sections 40E (both of which have respective remaining sections of metal oxide resist sublayers 40A–40D). After development, structured metal oxide resist layer 30' and structured metal oxide resist layer 40' exhibit resist structures corresponding to the IC structure of mask 30.Because metal oxide resist layer 40 has a dense and uniform structure, while metal oxide resist layer 30 has a loose and random structure, metal oxide resist layer 40 absorbs structured radiation more uniformly than metal oxide resist layer 30, and exposed sections 40E have relatively smooth edges and / or sidewalls compared to exposed sections 30E of metal oxide resist layer 30. Structured metal oxide resist layer 40' therefore exhibits better LER / LWR and critical dimensional uniformity than structured metal oxide resist layer 30', which significantly improves lithographic resolution. See, for example, top views of structured metal oxide resist layer 30' and structured metal oxide resist layer 40' in [reference missing]. Fig. 1C.

[0033] The present disclosure further discloses the use of a cyclic metal resist deposition process to control the density profile and / or density characteristics of a metal oxide resist layer in order to obtain desired performance of the metal oxide resist layer during structuring (i.e., exposure and development) and to optimize certain structural characteristics. In some embodiments, a number of cycles (i.e., a number of metal oxide sublayers), a thickness per cycle (i.e., thickness of the metal oxide sublayers), a density per cycle (i.e., densities of the metal oxide sublayers), and / or a cycle time can be tuned (adjusted) to achieve a desired density profile, desired density characteristics, and / or desired optimized performance parameters of a metal oxide resist layer.In some embodiments, parameters of the deposition processes, such as deposition processes 50-1 - 50-4, are adjusted to achieve the desired density profile, desired density characteristics, and / or desired optimized performance parameters of metal oxide resist sublayers. Deposition parameters may include precursor type, precursor flow rate, deposition pressure, deposition temperature, deposition power, deposition time, another deposition parameter, or combinations thereof. In some embodiments, parameters of the compaction processes, such as compaction processes 52-1 - 52-3, are adjusted to achieve the desired density profile, desired density characteristics, and / or desired optimized performance parameters of metal oxide resist sublayers.Compaction parameters can include treatment time, treatment temperature, treatment wavelength, treatment power, treatment pre-product, treatment pre-product flow, another treatment parameter, or combinations thereof.

[0034] Sometimes, during an exposure process, structured radiation may not expose a resist layer uniformly along its depth. For example, the top of the resist layer receives a higher exposure dose than the bottom. Absorption of exposure photons (e.g., EUV photons) can decrease accordingly from the top to the bottom of the resist layer, reducing cross-linking in the resist layer from top to bottom. This phenomenon can occur in lithography process A, as in Fig. Figure 2A shows that the number of EUV photons (P) in the top surfaces of exposed sections 30E of metal oxide resist layer 30 is lower than the number of EUV photons in the bottom surfaces of exposed sections 30E of metal oxide resist layer 30. Therefore, fewer chemical reactions (e.g., cross-linking) occur in the bottom surfaces of exposed sections 30E compared to the top surfaces of exposed sections 30E, and the bottom surfaces of exposed sections 30E are partially soluble in a developer (rather than insoluble). As a result, a resist structure defined by exposed sections 30E exhibits biases (differences) in critical top surface dimensions (TCDs) and critical bottom surface dimensions (BCDs), thus reducing the structural accuracy provided by the structured metal oxide resist layer 30'.In some embodiments, as shown, exposed sections 30E have conical side walls, wherein the widths of exposed sections 30E decrease from the top to the bottom and the TCDs of exposed sections 30E are larger than the BCDs of exposed sections 30E.

[0035] Lithography process C implements a cyclic metal resist deposition process B to provide a metal oxide resist layer 80, which is responsible for this phenomenon and optimizes the absorption of exposure photons (e.g., EUV photons) from the top to the bottom. The metal oxide resist layer 80 has a graded density that decreases from the bottom to the top, such as from a bottom surface of the metal oxide resist layer 80 (e.g., adjacent to material layer 20) to a top surface of the metal oxide resist layer 80. For example, a cyclic metal resist deposition process B forms a metal oxide resist sublayer 80A, a metal oxide resist sublayer 80B, and a metal oxide resist sublayer 80C, which together form a metal oxide resist layer 80 with thickness T.In contrast to metal oxide resist layer 40 (where metal oxide resist sublayers 40A–40D have essentially the same densities), the density of metal oxide resist sublayer 80A is greater than the density of metal oxide resist sublayer 80B, and the density of metal oxide resist sublayer 80B is greater than the density of metal oxide resist sublayer 80C, so the density of metal oxide resist layer 80 decreases from bottom to top. Configuring metal oxide resist layer 80 with a low-density top section (i.e., metal oxide resist sublayer 80C) allows exposure photons to more easily pass through metal oxide resist layer 80 to a bottom section of metal oxide layer 80, thus increasing the number of photons reaching the bottom section. Configuring metal oxide resist layer 80 with a high-density bottom section (i.e.,Configuring the metal oxide resist sublayer 80A increases the absorption of exposure photons by the bottom portion of the metal oxide resist layer 80. The graded density of the metal oxide resist layer 80 therefore increases cross-linking in the bottom portion of the metal oxide resist layer 80. For example, during the exposure process, the amount of chemical reactions (e.g., cross-linking) in the bottom portions of exposed sections 80E is essentially the same as the amount of chemical reactions in the top portions of exposed sections 80E, so exposed sections 80E become uniformly insoluble (e.g., from top to bottom) by a developer, while unexposed sections 80U remain soluble by the developer.As a result, after development, a resist structure is provided by a structured metal oxide resist layer 80' having openings 82 defined by exposed sections 80E, which exhibit minimal (to no) bias in TCDs and BCDs (i.e., TCDs are essentially the same as BCDs), thereby improving structural accuracy. In some embodiments, as shown, exposed sections 80E have essentially parallel sidewalls, and the widths of exposed sections 80E are essentially the same from top to bottom. In some embodiments, the top, low-density section of the metal oxide resist layer 80 has a loose, random, and / or non-uniform atomic structure, and the bottom, high-density section of the metal oxide resist layer 80 has a dense, ordered, and / or uniform atomic structure.

[0036] In some embodiments, the overall density (e.g., average density) of metal oxide resist layer 80 is greater than the overall density (e.g., average density) of metal oxide resist layer 30, such that metal oxide resist layer 80 can absorb more radiation than metal oxide resist layer 30 when exposed with the same dose, and can absorb this radiation more uniformly than metal oxide resist layer 30. In the illustrated embodiment, the density of metal oxide resist sublayer 80A and the density of metal oxide resist sublayer 80B are greater than the density of metal oxide resist layer 30, while the density of metal oxide resist sublayer 80C is essentially the same as or less than the density of metal oxide resist layer 30. In some embodiments, the densities of metal oxide resist sublayers 80A–80C are all greater than the density of metal oxide resist layer 30.Metal oxide sublayers 80A–80C can exhibit respective density profiles, such as a substantially uniform density, a graduated density that increases or decreases from a bottom surface to a top surface, a varying density, or another suitable density profile. In the illustrated embodiment, each of the metal oxide sublayers 80A–80C exhibits a substantially uniform density. In some embodiments, an atomic structure of metal oxide resist sublayer 80A is more ordered and / or more densely packed than an atomic structure of metal oxide resist sublayer 80B, and an atomic structure of metal oxide resist sublayer 80B is more ordered and / or more densely packed than an atomic structure of metal oxide resist sublayer 80C. Metal oxide resist sublayers 80A - 80C each have a thickness t5, a thickness t6 and a thickness t7, where a sum of thickness t5, thickness t6 and thickness t7 equals target thickness T.In the illustrated embodiment, thicknesses t5, t6, and t7 are essentially the same. In some embodiments, thicknesses t5, t6, and / or t7 are different and / or the same, depending on the desired density profile and / or density characteristics for the metal oxide resist layer 80.

[0037] Fig. Figure 2B illustrates the cyclic metal resist deposition process B according to various aspects of the present disclosure. Fig. 2B comprises cyclic metal resist deposition process B, comprising three cycles, each forming one of metal oxide resist sublayers 80A–80C. Each cycle includes a deposition process, and some cycles include a densification process. For example, cyclic metal resist deposition process B comprises Cycle 1, Cycle 2, and Cycle 3. Cycle 1 involves performing a deposition process 90-1 to form a metal oxide resist sublayer 80A', having a thickness t5 and a first density, on material layer 20, and performing a densification process 92-1 on metal oxide resist sublayer 80A', forming metal oxide resist sublayer 80A, which has a second density greater than the first density.Cycle 2 comprises performing a deposition process 90-2 to form a metal oxide resist sublayer 80B', having a thickness t6 and a third density, on metal oxide resist sublayer 80A, and performing a compaction process 92-2 on metal oxide resist sublayer 80B', thereby forming metal oxide resist sublayer 80B, which has a fourth density, greater than the third density and less than the second density of metal oxide resist sublayer 80A. Cycle 3 comprises performing a deposition process 90-3 to form metal oxide resist sublayer 80C, which has a fifth density, less than the fourth density. No compaction process is performed during Cycle 3.Deposition processes 90-1 - 90-3 are similar to deposition processes 50-1 - 50-4 previously described. Compaction processes 92-1 - 92-2 are similar to compaction processes 52-1 - 52-4. The parameters of deposition processes 90-1 - 90-3 and compaction processes 92-1, 92-2 can be configured to achieve desired density profiles and / or density characteristics of metal oxide resist sublayers 80A', 80B', metal oxide resist sublayers 80A - 80C, and metal oxide resist layer 80. In the illustrated embodiment, the second, fourth, and fifth densities (i.e., densities of the metal-and-oxygen-containing resist materials after each cycle) are different, such that metal oxide resist layer 80 has a density that increases from the top to the bottom. In some embodiments, the first density, the third density, and the fifth density (i.e.,The densities of the metal- and oxygen-containing resist materials (as deposited) are essentially the same. In some embodiments, the first density, the third density, and / or the fifth density are different. In some embodiments, the first density, the third density, and / or the fifth density are the same as the density of metal oxide resist layer 30.

[0038] Sometimes, during an exposure process, unplanned chemical reactions (e.g., cross-linking) occur in unexposed areas of a resist layer. This phenomenon can occur in lithography process A, as in Fig. Figure 3A shows that chemical reactions occur unintentionally and unplanned in sections of metal oxide resist layer 30 that are covered by mask 30 (i.e., unexposed sections 30U), forming unplanned exposed sections UE that are partially insoluble (rather than soluble) by a developer. As a result, unexposed sections 30U are not completely removed by the developer, leaving resist residues S in unexposed areas of workpiece 10. Resist residues S correspond to unplanned exposed sections UE, which can be resist removal (e.g., resist residues that prevent areas of material layer 20 from being textured) and / or resist set (e.g., resist residues at the bottoms of exposed sections 30E that cause critical dimensional variations and / or LER / LWR variations). Lithography process D, in Fig. Figure 3A implements a cyclic metal resist deposition process C to provide a metal oxide resist layer 100 which is responsible for the phenomenon and minimizes it.

[0039] The metal oxide resist layer 100 has a graded density that increases from the bottom to the top, such as from a bottom surface of the metal oxide resist layer 100 (e.g., adjacent to material layer 20) to a top surface of the metal oxide resist layer 100. For example, cyclic metal resist deposition process C forms a metal oxide resist sublayer 100A, a metal oxide resist sublayer 100B, and a metal oxide resist sublayer 100C, which together form a metal oxide resist layer 100 with thickness T. In contrast to metal oxide resist layer 40 (where metal oxide resist sublayers 40A - 40D have essentially the same densities), the density of metal oxide resist sublayer 100A is lower than the density of metal oxide resist sublayer 100B, and the density of metal oxide resist sublayer 100B is lower than the density of metal oxide resist sublayer 100C, so the density of metal oxide resist layer 100 increases from bottom to top.Configuring the metal oxide resist layer 100 with a low-density bottom section (i.e., metal oxide resist sublayer 100A) reduces the absorption of exposure photons by the bottom section of the metal oxide resist layer 100 and thus reduces the frequency of unplanned chemical reactions in unexposed sections of the metal oxide resist layer 100. Conversely, configuring the metal oxide resist layer 100 with a high-density top section (i.e., metal oxide resist sublayer 100B and metal oxide resist sublayer 100C) increases the absorption of exposure photons by the top section of the metal oxide resist layer 100. The graded density of the metal oxide resist layer 100 therefore decreases cross-linking in the bottom section of the metal oxide resist layer 100, while increasing cross-linking in the top section. For example, during the exposure process, a number of chemical reactions can occur (e.g.Cross-linking in the bottom sections of exposed sections 100E is less than the amount of chemical reactions in the top sections of exposed sections 100E, thereby reducing the frequency of unplanned chemical reactions, such as partial cross-linking, in unexposed sections 100U adjacent to the bottom sections of exposed sections 100E. As a result, after development, a resist structure is provided by a structured metal oxide resist layer 100', which has openings 102 defined by well-defined exposed sections 100E with minimal to no resist residue, thereby improving structural accuracy. In some embodiments, as shown, exposed sections 100E have substantially parallel sidewalls, and the widths of exposed sections 100E are substantially the same from the top to the bottom.In some embodiments, the low-density bottom section of metal oxide resist layer 100 has a loose, random and / or non-uniform atomic structure, and the high-density top section of metal oxide resist layer 100 has a dense, ordered and / or uniform atomic structure.

[0040] In some embodiments, the overall density (e.g., average density) of metal oxide resist layer 100 is greater than the overall density (e.g., average density) of metal oxide resist layer 30, such that metal oxide resist layer 100 can absorb more radiation than metal oxide resist layer 30 when exposed to the same dose, and can absorb this radiation more uniformly than metal oxide resist layer 30. In the illustrated embodiment, the density of metal oxide resist sublayer 100C and the density of metal oxide resist sublayer 100B are greater than the density of metal oxide resist layer 30, while the density of metal oxide resist sublayer 100A is substantially the same as or less than the density of metal oxide resist layer 30. In support of the illustrated embodiment, the density of metal oxide resist sublayer 100C is greater than the density of metal oxide resist sublayer 100B.In some embodiments, the density of metal oxide resist sublayer 100C and the density of metal oxide resist sublayer 100B are essentially the same. In some embodiments, the densities of metal oxide resist sublayers 100A–100C are all greater than the density of metal oxide resist layer 30. Metal oxide sublayers 100A–100C may exhibit respective density profiles, such as a substantially uniform density, a graduated density that increases or decreases from a bottom surface to a top surface, a varying density, or another suitable density profile. In the illustrated embodiment, each of the metal oxide sublayers 100A–100C has a substantially uniform density.In some embodiments, the atomic structure of metal oxide resist sublayer 100A is less ordered and / or more densely packed than that of metal oxide resist sublayer 100B, and vice versa. Metal oxide resist sublayers 100A–100C each have a thickness t8, a thickness t9, and a thickness t10, where the sum of these thicknesses equals the target thickness T. In the illustrated embodiment, thicknesses t8, t9, and t10 are essentially the same. In some embodiments, thicknesses t8, t9, and / or t10 are different and / or the same, depending on the desired density profile and / or density characteristics.

[0041] Fig. Figure 3B illustrates a cyclic metal resist deposition process C according to various aspects of the present disclosure. Fig. Cyclic metal resist deposition process C comprises three cycles, each forming one of metal oxide resist sublayers 100A-100C. Each cycle includes a deposition process, and some cycles include a densification process. For example, cyclic metal resist deposition process C comprises Cycle 1, Cycle 2, and Cycle 3. Cycle 1 involves performing a deposition process 100-1 to form a metal oxide resist sublayer 100A with a thickness t8 and an initial density on material layer 20. No densification process is performed during Cycle 1.Cycle 2 comprises performing a deposition process 110-2 to form a metal oxide resist sublayer 100B' with thickness t9 and a second density on metal oxide resist sublayer 100A, and performing a compaction process 112-1 on metal oxide resist sublayer 100B', thereby forming metal oxide resist sublayer 100B with a third density that is greater than the second density and the first density of metal oxide resist sublayer 100A. Cycle 3 includes performing a deposition process 100-3 to form metal oxide resist sublayer 100C' with thickness t10 and a fourth density, and performing a compaction process 112-2 on metal oxide resist sublayer 100C', thereby forming metal oxide resist sublayer 100C with a fifth density greater than the fourth density and the third density of metal oxide resist sublayer 100B.Deposition processes 110-1 - 110-3 are similar to deposition processes 50-1 - 50-4 previously described, compaction processes 112-1, 112-2 are similar to compaction processes 52-1 - 52-4 and parameters of deposition processes 110-1 - 110-3 and compaction processes 112-1, 112-2 can be configured to achieve desired density profiles and / or desired density characteristics of metal oxide resist sublayers 100B', 100C', metal oxide resist sublayers 100A - 100C and metal oxide resist layer 100. In the illustrated embodiment, the first density, the third density, and the fifth density (i.e., the densities of the metal-and-oxygen-containing resist materials after each cycle) are different, such that the metal oxide resist layer 100 has a density that decreases from the top to the bottom. In some embodiments, the third and fifth densities are the same, but different from and greater than the first density.In some embodiments, the first density, the second density, and the fourth density (i.e., densities of the metal-and-oxygen-containing resist materials as deposited) are essentially the same. In some embodiments, the first density, the second density, and / or the fourth density are different. In some embodiments, the first density, the second density, and / or the fourth density are the same as the density of metal oxide resist layer 30.

[0042] Fig. Figure 4 illustrates a cyclic metal resist deposition process D for forming a metal oxide resist layer 120, which can be used in a lithography process to improve structural accuracy according to various aspects of the present disclosure. The metal oxide resist layer 120 has a varying density from bottom to top (e.g., loose-dense-loose-dense), such as from a bottom surface of the metal oxide layer 120 (e.g., adjacent to material layer 20) to a top surface of the metal oxide resist layer 120. For example, the cyclic metal resist deposition process D forms a metal oxide resist sublayer 120A, a metal oxide resist sublayer 120B, a metal oxide resist sublayer 120C, and a metal oxide resist sublayer 120D, which together form a metal oxide resist layer 120 with thickness T.Metal oxide resist sublayers 120A - 120D each have a thickness t11, a thickness t12, a thickness t13 and a thickness t14, where a sum of thickness t11, thickness t12, thickness t13 and thickness t14 equals target thickness T. In contrast to metal oxide resist layer 40 (where metal oxide resist sublayers 40A - 40D have essentially the same densities), the density of metal oxide resist sublayer 120B is greater than the density of metal oxide resist sublayer 120A, the density of metal oxide resist sublayer 120C is less than the density of metal oxide resist sublayer 120B, and the density of metal oxide resist sublayer 120D is greater than the density of metal oxide resist sublayer 120C, so that the density of metal oxide resist layer 120 alternates low-high and / or the atomic structure of metal oxide resist layer 120 alternates loose-dense from bottom to top.A varying density profile can balance various structuring concerns to optimize structural accuracy. For example, configuring metal oxide resist layer 120 with a low-density bottom section (i.e., metal oxide resist sublayer 120A) reduces resist erosion and / or resist base defects, while configuring metal oxide resist layer 120 with a high-density top section (i.e., metal oxide resist sublayer 120D) minimizes outgassing and thus outgassing contamination originating from the metal oxide resist layer 120. Furthermore, configuring metal oxide resist layer 120 with a middle section of graduated density that decreases from top to bottom (i.e., metal oxide resist sublayer 120B and metal oxide resist sublayer 120C) can improve radiation absorption, thereby enhancing LER / LWR and / or critical dimensional uniformity.

[0043] In some embodiments, the overall density (e.g., average density) of metal oxide resist layer 120 is greater than the overall density (e.g., average density) of metal oxide resist layer 30, such that metal oxide resist layer 120 can absorb more radiation than metal oxide resist layer 30 when exposed to the same radiation dose, and absorbs this radiation more uniformly than metal oxide resist layer 30. In the illustrated embodiment, the densities of metal oxide resist sublayers 120B–120D are greater than the density of metal oxide resist layer 30, while the density of metal oxide resist sublayer 120A is essentially the same as or less than the density of metal oxide resist layer 30.In some embodiments, the density of metal oxide resist sublayer 120D is a maximum density of metal oxide resist layer 120, the density of metal oxide resist sublayer 120A is a minimum density of metal oxide resist layer 120, and the density of metal oxide resist sublayer 120C is between the maximum and minimum densities. In some embodiments, the density of metal oxide resist sublayer 120B is the same as the density of metal oxide resist sublayer 120D. In some embodiments, the density of metal oxide resist sublayer 120B is less than the density of metal oxide resist sublayer 120D but greater than the density of metal oxide resist sublayer 120C. In some embodiments, the densities of metal oxide resist sublayers 120A–120D are all greater than the density of metal oxide resist layer 30.Metal oxide sublayers 120A–120D can have respective density profiles, such as a substantially uniform density, a graduated density that increases or decreases from a bottom surface to a top surface, a varying density, or another suitable density profile. In the illustrated embodiment, each of the metal oxide sublayers 120A–120D has a substantially uniform density.

[0044] In Fig. Cyclic metal resist deposition process D comprises four cycles, each forming one of metal oxide resist sublayers 120A–120D. Each cycle includes a deposition process, and some cycles include a densification process. For example, cyclic metal resist deposition process D comprises cycle 1, cycle 2, cycle 3, and cycle 4. Cycle 1 involves performing a deposition process 130-1 to form metal oxide resist sublayer 130A with thickness t11 and an initial density on material layer 20. No densification process is performed during cycle 1.Cycle 2 comprises performing a deposition process 130-2 to form a metal oxide resist sublayer 120B' with thickness t12 and a second density on top of metal oxide resist sublayer 120A, and performing a compaction process 132-1 on metal oxide resist sublayer 120B', thereby forming metal oxide resist sublayer 120B with a third density greater than both the second and first densities of metal oxide resist sublayer 120A. Thickness t12 is greater than thickness t11. Cycle 3 comprises performing a deposition process 130-3 to form metal oxide resist sublayer 120C' with thickness t13 and a fourth density, and performing a compaction process 132-2 on metal oxide resist sublayer 120C', thereby forming metal oxide resist sublayer 120C with a fifth density, greater than the fourth density and less than the third density of metal oxide resist sublayer 120B. Thickness t13 is less than thickness t12 and greater than thickness t11.Cycle 4 comprises performing a deposition process 130-4 to form metal oxide resist sublayer 120D' with thickness t14 and a sixth density, and performing a compaction process 132-3 on metal oxide resist sublayer 120D', thereby forming metal oxide resist sublayer 120D with a seventh density, greater than the sixth density and greater than the fifth density of metal oxide resist sublayer 120C. Thickness t14 is less than thickness t13. In the illustrated embodiment, the seventh density is essentially the same as the third density.Deposition processes 130-1 - 130-4 are similar to deposition processes 50-1 - 50-4 previously described, compaction processes 132-1 - 132-3 are similar to compaction processes 52-1 - 52-4, and the parameters of deposition processes 130-1 - 130-4 and compaction processes 132-1 - 132-3 can be configured to achieve desired density profiles and / or desired density characteristics of metal oxide resist sublayers 120B' - 120D', metal oxide resist sublayers 120A - 120D, and metal oxide resist layer 120. In the illustrated embodiment, the first density, the third density, the fifth density, and the seventh density (i.e., densities of the metal-and-oxygen-containing resist materials after each cycle) are different, such that the metal oxide resist layer 120 has a density that varies from the top to the bottom. In some embodiments, the first density, the second density, the fourth density, and / or the sixth density (i.e.,The densities of the metal- and oxygen-containing resist materials (as deposited) are essentially the same. In some embodiments, the first density, the second density, and / or the fourth density are different. In some embodiments, the first density, the second density, the fourth density, and / or the sixth density are the same as the density of metal oxide resist layer 30. Fig. Section 4 has been simplified for clarity to facilitate understanding of the inventive concepts of the present disclosure. Additional features may be added to the cyclic metal resist deposition process D, and some of the features described below may be replaced, modified, or eliminated in other embodiments of the cyclic metal resist deposition process D.

[0045] Fig. Figure 5 illustrates a cyclic metal resist deposition process E for forming a metal oxide resist layer that can be used in a lithography process to improve structural accuracy according to various aspects of this disclosure. Cyclic metal resist deposition process E is similar to cyclic metal oxide resist deposition process A, except that cyclic metal resist deposition process E forms a metal oxide resist layer 140 and coordinates densification processes to induce partial cross-linking in the metal oxide resist layer 140. For example, the metal oxide resist layer 140 is uniformly, partially cross-linked from bottom to top, such as from a bottom surface of the metal oxide resist layer 140 (e.g., adjacent to material layer 20) to a top surface of the metal oxide resist layer 140.The degree of cross-linking in metal oxide resist layer 140 is greater than the degree of cross-linking in metal oxide resist layer 130 (which can be zero), so metal oxide resist layer 140 can be structured with a smaller exposure dose than is required for metal oxide resist layer 30. Fig. In process 5, a cyclic metal resist deposition process E forms a metal oxide resist sublayer 140A, a metal oxide resist sublayer 140B, a metal oxide resist sublayer 140C, and a metal oxide resist sublayer 140D, which together form a metal oxide resist layer 140 with thickness T. The metal oxide resist sublayers 140A–140D each have thicknesses t1, t2, t3, and t4, respectively, where the sum of these thicknesses equals the target thickness T. The degree of partial cross-linking in metal oxide resist sublayer 140A, the degree of partial cross-linking in metal oxide resist sublayer 140B, the degree of partial cross-linking in metal oxide resist sublayer 140C, and the degree of partial cross-linking in metal oxide resist sublayer 140D are essentially the same. In the illustrated embodiment, thicknesses t1, t2, t3, and t4 are essentially the same.In some embodiments, thickness t1, thickness t2, thickness t3 and / or thickness t4 are different or the same, depending on the desired partial cross-linking profile. Fig. Section 5 has been simplified for clarity and to facilitate understanding of the inventive concepts of the present disclosure. Additional features may be added to the cyclic metal resist deposition process E, and some of the features described below may be replaced, modified, or eliminated in other embodiments of the cyclic metal resist deposition process E.

[0046] In Fig. 5. Cyclic metal resist deposition process E comprises four cycles, each cycle forming one of metal oxide resist sublayers 140A–140D, and each cycle including a deposition process and a compaction process. For example, cyclic metal resist deposition process E comprises a cycle 1, a cycle 2, a cycle 3, and a cycle 4, where cycles 1–4 include deposition processes 50-1–50-4, each forming metal oxide resist sublayers 40A'–40D' as previously described. Fig.Cycles 1A-1C are described. Cycle 1 involves performing a compaction process 152-1 to induce cross-linking in metal oxide resist sublayer 40A', thereby providing metal oxide resist sublayer 140A with a first degree of cross-linking. Cycle 2 involves performing a compaction process 152-2 to induce cross-linking in metal oxide resist sublayer 40B', thereby providing metal oxide resist sublayer 140B with a second degree of cross-linking. Cycle 3 involves performing a compaction process 152-3 to induce cross-linking in metal oxide resist sublayer 40C', thereby providing metal oxide resist sublayer 140C with a third degree of cross-linking. Cycle 4 includes performing a compaction process 152-4 to induce cross-linking in metal oxide resist sublayer 40D', thereby providing metal oxide resist sublayer 140D with a fourth degree of cross-linking.The first, second, third, and fourth degrees of cross-linking are less than complete cross-linking. In the illustrated embodiment, the first, second, third, and fourth degrees of cross-linking are essentially the same, which can be achieved by adjusting the parameters of the compaction processes 152-1–152-4. In some embodiments, the first, second, third, and fourth degrees of cross-linking are different and / or the same to achieve metal oxide resist layers with different cross-linking profiles. In some embodiments, the metal oxide resist layer 140 exhibits a degree of cross-linking that varies from the top to the bottom. For example, the first degree of cross-linking is greater than the second, third, and / or fourth degrees of cross-linking. Compaction processes 152-1–152-4 are similar to previously described compaction processes.For example, compaction processes can include 152-1 - 152-4 softbakes, UV treatments, IR treatments, other suitable treatments or combinations thereof.

[0047] After performing the various lithography processes described herein (e.g., lithography process A, lithography process B, lithography process C and / or lithography processes), a densification process is performed on workpiece 10, such as material layer 20 and / or wafer 15, using the structured metal oxide resist layers described herein (e.g., structured metal oxide resist layer 30', structured metal oxide resist layer 40', structured metal oxide resist layer 80', structured metal oxide resist layer 100', structured metal oxide resist layer formed from metal oxide resist layer 120, and / or structured metal oxide resist layer formed from metal oxide resist layer 140) as masks.For example, the manufacturing process is applied only to sections of workpiece 10 within openings in the structured metal oxide resist layers, while other sections of workpiece 10, which are covered by the structured metal oxide resist layers (for example, by exposed sections of the structured metal oxide resist layers), are protected from the manufacturing process. In some embodiments, the manufacturing process includes etching of material layer 20 using the structured metal oxide resist layers as etch masks. A structure is thus transferred from the structured metal oxide resist layers to material layer 20, thereby forming a structured material layer.In embodiments where material layer 20 is a hard mask layer, the structure is first transferred from the structured metal oxide resist layers to material layer 20, and then the structure is transferred from the structured material layer 20 to a material layer of wafer 15. In some embodiments, the manufacturing process includes performing an implantation process on material layer 20 using the structured metal oxide resist layers as an implantation mask, thereby forming various doped features (regions) in material layer 20. In some embodiments, the manufacturing process includes depositing a material over material layer 20 using the structured metal oxide resist layers as a deposition mask, thereby forming various material features (e.g., gates and / or contacts) over material layer 20.The structured metal oxide resist layers are then removed from workpiece 10 using any suitable process. In some embodiments, the structured metal oxide resist layers may be partially consumed during the manufacturing process, such as during the etching process, so that any remaining portion of the structured metal oxide resist layers is subsequently removed by a suitable process.

[0048] This disclosure provides metal oxide resist layers, cyclic metal oxide resist deposition processes for forming the metal oxide resist layers, and lithography techniques implementing the metal oxide resist layers to improve lithography resolution and / or resist structure accuracy. This disclosure considers that the cyclic metal oxide resist deposition processes described herein can be implemented to form any type of metal-containing resist layer, such as a metal nitride resist layer, a metal carbide resist layer, and / or any other type of photosensitive layer containing metal. In such embodiments, references to oxygen / oxide can be replaced by references to other constituents, such as nitrogen / nitride, carbon / carbide, and / or other metal-containing resist constituents.In such embodiments, the metal-containing resist layers may or may not contain oxygen. The advanced lithography processes, methods, and materials described above can be used in many applications, including FinFETs and / or GAA transistors. For example, fins can be structured to create a relatively narrow spacing between features, as described above. Additionally, spacers used in the formation of fins, also referred to as spindles, can be processed according to the above disclosure.

[0049] A method according to the invention comprises forming a metal oxide resist layer over a workpiece by performing deposition processes to form metal oxide resist sublayers over the workpiece and performing a densification process on at least one of the metal oxide resist sublayers. Each deposition process forms one of the metal oxide resist sublayers. According to the invention, the densification process increases the density of at least one of the metal oxide resist sublayers. Parameters of the deposition processes and / or parameters of the densification process can be adjusted to achieve different density profiles, different density characteristics, and / or different absorption characteristics in order to optimize the structuring of the metal oxide resist layer. In some embodiments, forming the metal oxide resist layer further comprises performing a cleaning process after the densification process.In some embodiments, the deposition and densification processes are carried out in the same process chamber. In some embodiments, performing the densification process includes exposing at least one of the metal oxide resist sublayers to a plasma. In some embodiments, performing the densification process includes soft baking of at least one of the metal oxide resist sublayers. In some embodiments, performing the densification process includes irradiating at least one of the metal oxide resist sublayers with ultraviolet radiation (UV radiation). In some embodiments, performing the densification process includes irradiating at least one of the metal oxide resist sublayers with infrared radiation (IR radiation). According to the invention, the densification process is carried out after each deposition cycle, so that each of the metal oxide resist sublayers is subjected to a separate densification treatment.In some embodiments, the method further comprises adjusting the deposition parameters of the deposition processes, adjusting the compaction parameters of the compaction process, or both, to achieve a graduated density in the metal oxide resist layer. In some embodiments, the method further comprises performing an exposure process on the metal oxide resist layer and performing a development process on the metal oxide resist layer, thereby forming a structured metal oxide resist layer over the workpiece.

[0050] Another method according to the invention comprises receiving a workpiece in a process chamber; performing at least two deposition processes in the process chamber to form a metal oxide resist layer over the workpiece; and performing a treatment process in the process chamber to modify the density profile of the metal oxide resist layer. According to the invention, the treatment process is performed after each of the at least two deposition processes, such that the metal oxide resist layer has a varying density from the bottom to the top. In some embodiments, the treatment process is performed after at least one of the at least two deposition processes, such that the metal oxide resist layer has a graduated density that increases from the bottom to the top.In some embodiments, the treatment process is carried out after at least one of the at least two deposition processes, such that the metal oxide resist layer has a graduated density that decreases from the bottom to the top. In some embodiments, the treatment process is carried out after at least one of the at least two deposition processes, such that the metal oxide resist layer has a varying density.

[0051] A metal oxide resist layer according to the invention comprises a first metal oxide resist sublayer, a second metal oxide resist sublayer arranged above the first metal oxide resist sublayer, and a third metal oxide resist sublayer arranged above the second metal oxide resist sublayer. The first metal oxide resist sublayer has a first density, the second metal oxide resist sublayer has a second density, and the third metal oxide resist sublayer has a third density. According to the invention, the first, second, and third densities are different. In some embodiments, the first, second, and third densities are configured to provide the metal oxide resist layer with a graduated density from the first metal oxide resist sublayer to the third metal oxide resist sublayer.

[0052] Another unclaimed method comprises forming a metal oxide resist layer over a workpiece by performing a deposition process comprising more than one deposition cycle, such that the metal oxide resist layer has a stack of metal oxide resist sublayers, and performing a densification process on at least one of the metal oxide resist sublayers, wherein the densification process increases the density of the at least one of the metal oxide resist sublayers. In some embodiments, performing the deposition process and performing the densification process are carried out in the same process chamber. In some embodiments, performing the densification process comprises exposing the at least one of the metal oxide resist sublayers to a plasma. In some embodiments, performing the densification process comprises exposing the at least one of the metal oxide resist sublayers to a tempering process.In some embodiments, performing the compaction process includes exposing at least one of the metal oxide resist sublayers to ultraviolet (UV) radiation. In some embodiments, performing the compaction process includes exposing at least one of the metal oxide resist sublayers to infrared (IR) radiation. In some embodiments, the deposition process is a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, or a combination thereof. In some embodiments, the compaction process is performed after each deposition cycle, so that each of the metal oxide resist sublayers in the stack of metal oxide resist sublayers undergoes a separate compaction treatment.In some embodiments, the method further comprises adjusting the execution of the deposition process, adjusting the execution of the compaction process, or both, to achieve a graded density in the metal oxide resist layer. In some embodiments, a first density of an uppermost metal oxide resist sublayer of the stack of metal oxide resist sublayers is greater than a second density of a lowermost metal oxide resist sublayer of the stack of metal oxide resist sublayers. In some embodiments, a first density of an uppermost metal oxide resist sublayer of the stack of metal oxide resist sublayers is less than a second density of a lowermost metal oxide resist sublayer of the stack of metal oxide resist sublayers.In some embodiments, tuning the deposition process includes adjusting a precursor gas, a precursor gas flow, a deposition pressure, a deposition temperature, a deposition power, a deposition time, another deposition parameter, or a combination thereof. In some embodiments, tuning the compaction process includes adjusting a treatment time, a treatment power, a treatment temperature, another treatment parameter, or a combination thereof. In some embodiments, the method further includes tuning the deposition process, tuning the compaction process, or both, to achieve a varying density structure in the stack of metal oxide resist sublayers. In some embodiments, the method further includes performing a cleaning process after the compaction process.In some embodiments, the compaction process is a first compaction process, and the method further comprises performing a second compaction process before forming the metal oxide resist layer over the workpiece. In some embodiments, the method further comprises performing an exposure process on the metal oxide resist layer and performing a development process on the metal oxide resist layer, thereby forming a structured metal oxide resist layer over the workpiece. In some embodiments, the compaction process is a first compaction process, and the method further comprises performing the exposure process, which includes exposing the metal oxide resist layer with structured extreme ultraviolet radiation (ELTV radiation).In some embodiments, the method further comprises performing an etching, implantation, or deposition process on the workpiece using the structured metal oxide resist layer as an etching mask, implantation mask, or deposition mask, respectively. In some embodiments, the method comprises removing the structured metal oxide resist layer after the etching, implantation, or deposition process. In some embodiments, the method further comprises transferring a structure in the structured metal oxide resist layer to a sacrificial layer placed above the workpiece, thereby forming a structured sacrificial layer, and transferring a structure in the structured sacrificial layer to a material layer of the workpiece.In some embodiments, the process further includes carrying out a compaction process on the workpiece before forming the metal oxide resist layer.

Claims

[1] Procedure encompassing: Forming a metal oxide resist layer (40) over a workpiece (10) by: - Performing deposition processes to form metal oxide resist sublayers (40A, 40B, 40C, 40D) over the workpiece (10), each deposition process forming a respective metal oxide resist sublayer (40A, 40B, 40C, 40D) of the metal oxide resist sublayers (40A, 40B, 40C, 40D); and - Performing a compaction process on at least one of the metal oxide resist sublayers (40A, 40B, 40C, 40D), wherein the compaction process increases the density of at least one of the metal oxide resist sublayers (40A, 40B, 40C, 40D), and wherein the compaction process is performed after each deposition cycle, so that each of the metal oxide resist sublayers (40A, 40B, 40C, 40D) is subjected to a respective compaction treatment. [2] Method according to claim 1, wherein forming the metal oxide resist layer (40) further comprises: Performing a cleaning process after performing the compaction process. [3] Method according to claim 1 or 2, wherein the deposition processes and the condensation process are carried out in the same process chamber. [4] Method according to any one of claims 1 to 3, wherein carrying out the compaction process comprises: Exposure of at least one of the metal oxide resist sublayers (40A, 40B, 40C, 40D) to a plasma. [5] Method according to any one of claims 1 to 3, wherein carrying out the compaction process comprises softbaking of at least one of the metal oxide resist sublayers (40A, 40B, 40C, 40D). [6] Method according to any one of claims 1 to 3 above, comprising carrying out the compaction process: Exposure of at least one of the metal oxide resist sublayers (40A, 40B, 40C, 40D) with UV radiation. [7] Method according to any one of claims 1 to 3, wherein carrying out the compaction process comprises: Exposure of at least one of the metal oxide resist sublayers (40A, 40B, 40C, 40D) with infrared radiation, . [8] Method according to any of the foregoing claims, further comprising: Adjusting deposition parameters of the deposition processes, adjusting compaction parameters of the compaction process, or both, to achieve a density gradient in the metal oxide resist layer (40). [9] Method according to any of the foregoing claims, further comprising: Performing an exposure process on the metal oxide resist layer (40); and Performing a development process on the metal oxide resist layer (40), thereby forming a structured metal oxide resist layer (40) over the workpiece (10). [10] Procedures, including: Picking up a workpiece (10) in a process chamber; in the process chamber, carrying out at least two deposition processes to form a metal oxide resist layer (40) over the workpiece (10); and in the process chamber, performing a treatment process to modify a density profile of the metal oxide resist layer (40), wherein the treatment process is performed after each of the at least two deposition processes, such that the metal oxide resist layer (40) has a varying density from bottom to top. [11] Method according to claim 10, wherein the treatment process is carried out after at least one of the at least two deposition processes, such that the metal oxide resist layer (40) has a density gradient which increases from bottom to top. [12] Method according to claim 10, wherein the treatment process is carried out after at least one of the at least two deposition processes, such that the metal oxide resist layer (40) has a density gradient that decreases from bottom to top. [13] Method according to claim 10, wherein the treatment process is carried out after at least one of the at least two deposition processes, such that the metal oxide resist layer (40) has an alternating density. [14] comprising a metal oxide resist layer (40): a first metal oxide resist sublayer (40A) with a first density; a second metal oxide resist sublayer (40B) arranged above the first metal oxide resist sublayer (40A), wherein the second metal oxide resist sublayer (40B) has a second density; and a third metal oxide resist sublayer (40C) arranged above the second metal oxide resist sublayer (40B), wherein the third metal oxide resist sublayer (40C) has a third density, the first density, the second density and the third density being different from each other. [15] Metal oxide resist layer (409) according to claim 14, wherein the first density, the second density and the third density are configured to provide the metal oxide resist layer (40) with a density gradient from the first metal oxide resist sublayer (40A) to the third metal oxide resist sublayer (40C).

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