Baking method for improving the lithography performance of metal-containing resists

Abstract

This invention provides a baking method for improving the lithography performance of metal-containing resists. [Solution] Various embodiments of this specification relate to methods, apparatus, and systems for baking metal-containing materials on a semiconductor substrate in the presence of a reactive gas species. For example, this method may include receiving a substrate having a photoresist layer thereon into a processing chamber, the photoresist layer comprising a metal-containing photoresist material, flowing a reactive gas species from a gas source through a gas supply line into the processing chamber, exposing the substrate to the reactive gas species in the processing chamber, and baking the photoresist layer while the substrate is exposed to the reactive gas species.

Description

[Technical Field]

[0001] Reference As part of this application, a PCT application is filed concurrently with this specification. All applications identified in the concurrently filed PCT applications, for which this application claims interest or priority, are incorporated herein by reference for all purposes.

[0002] This disclosure generally relates to the semiconductor processing field. In particular aspects, this disclosure relates to processes and apparatus for photoresist processing related to lithography patterning and film development for forming pattern masks. [Background technology]

[0003] As semiconductor manufacturing advances, feature sizes continue to shrink, necessitating new processing methods. One area of ​​progress is related to patterning using photoresist materials, which are patterned by exposure to radiation.

[0004] The background art described herein is intended to provide a general overview of the contents of this disclosure. The inventors' inventions mentioned herein are not explicitly or implicitly recognized as prior art to this disclosure, not only in the background art section but also to the extent described in the manner in which the prior art is not recognized at the time of filing. [Overview of the project]

[0005] Various embodiments of this specification relate to methods, apparatus, and systems for baking a photoresist layer on a substrate. One embodiment of the embodiments of this disclosure provides a method for baking a photoresist layer on a substrate, the method comprising: receiving a substrate into a processing chamber, the substrate comprising a photoresist layer having a photoresist layer thereon comprising a metal-containing photoresist material; flowing a reaction gas species from a gas source through a gas supply line into the processing chamber; exposing the substrate to the reaction gas species within the processing chamber; and baking the photoresist layer while the substrate is exposed to the reaction gas species.

[0006] In various embodiments, the photoresist layer comprises an extreme ultraviolet (EUV) photoresist material. In some embodiments, the reaction gas species comprises a gas selected from the group consisting of water, hydrogen, oxygen, ozone, hydrogen peroxide, carbon monoxide, carbon dioxide, ammonia, nitrous oxide, nitric oxide, alcohol, acetylacetone, formic acid, oxalyl chloride, pyridine, carboxylic acids, amines, and combinations thereof. In some cases, the reaction gas species may include water. In other cases, the reaction gas species may include hydrogen. In other cases, the reaction gas species may include oxygen. In other cases, the reaction gas species may include ozone. In other cases, the reaction gas species may include hydrogen peroxide. In other cases, the reaction gas species may include carbon monoxide. In other cases, the reaction gas species may include carbon dioxide. In other cases, the reaction gas species may include ammonia. In some such cases, baking of the photoresist occurs after the photoresist has been exposed to EUV rays to pattern the photoresist, and one of the following conditions is met: (i) The processing chamber is maintained at atmospheric pressure during the baking of the photoresist, and ammonia is supplied at a concentration of about 0.001–5 (vol)%, and (ii) The processing chamber is maintained at near-atmospheric pressure during the baking of the photoresist, and ammonia is supplied at a partial pressure of about 1–100 mTorr. In these cases or otherwise, the reaction gas species may include nitrous oxide and / or nitric oxide. In these cases or otherwise, the reaction gas species may include alcohols. In these cases or otherwise, the reaction gas species may include acetylacetone. In these cases or otherwise, the reaction gas species may include formic acid. In these cases or otherwise, the reaction gas species may include oxalyl chloride. In these cases or otherwise, the reaction gas species may include carboxylic acids. In these cases or otherwise, the reaction gas species may include amines. Examples of amines may, in certain cases, include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, and / or triethylamine.In various embodiments, the reaction gas species may be oxidizing. In these and other cases, the reaction gas species may be polar.

[0007] In certain embodiments, exposure of the substrate to a reactive gas species may promote crosslinking in the photoresist layer. In these embodiments or other embodiments, exposure of the substrate to a reactive gas species may promote the removal of low molecular weight species within the photoresist layer. For example, low molecular weight species may contain zero, one, or two metal atoms per molecule. In some embodiments, exposure of the substrate to a reactive gas species may oxidize metal hydride species within the photoresist layer to metal hydroxide species.

[0008] In certain embodiments, this method may further comprise applying a vacuum to the processing chamber while the photoresist layer is being baked. In these or other embodiments, this method may further comprise controlling the moisture concentration in the processing chamber to remain within a target moisture concentration range while the photoresist layer is being baked. Similarly, this method may comprise controlling the oxygen concentration in the processing chamber to remain within a target oxygen concentration range while the photoresist layer is being baked. In some embodiments, the processing chamber may be maintained below atmospheric pressure while the photoresist layer is being baked. For example, in some cases, the processing chamber may be maintained below atmospheric pressure while the photoresist layer is being baked.

[0009] The support on which the substrate is mounted may be temperature-controlled during the baking of the photoresist layer. For example, in some embodiments, this method may further include raising the temperature of the substrate support on which the substrate is mounted during the baking of the photoresist layer. In these embodiments or other embodiments, this method may further include lowering the temperature of the substrate support on which the substrate is mounted during the baking of the photoresist layer. In some cases, this method may include controlling the reaction seed flow to the processing chamber to achieve a target degree of crosslinking. Various different types of heat may be provided. In some embodiments, baking the photoresist includes heating the substrate on a hot plate. In some embodiments, baking the photoresist layer includes exposing the substrate to infrared and / or ultraviolet light. In some embodiments, baking the photoresist layer may include heating the substrate from above. In these embodiments or other embodiments, baking the photoresist layer may include heating the substrate from below.

[0010] The methods described herein may be used for different applications. In some cases, the photoresist layer is coated onto the substrate but not yet patterned, and baking is post-coating bake (PAB). In other cases, the photoresist layer is coated onto the substrate and patterned by partial exposure to EUV rays, resulting in exposed and unexposed areas of the photoresist layer, and baking is post-exposure bake (PEB). In these or other embodiments, the reaction gas species may include polar and oxidizing molecules. For example, the reaction gas species may include hydrogen peroxide.

[0011] Another embodiment of the present disclosure provides an apparatus for baking a photoresist layer on a substrate. The apparatus comprises a processing chamber, an inlet for introducing a reaction gas species into the processing chamber, an outlet for removing material from the processing chamber, a substrate support within the processing chamber, a heater configured to heat the substrate by conduction, convection, and / or radiation, and a controller having at least one processor, the at least one processor configured to control the apparatus to perform the method of the present application or the method described herein.

[0012] These and other embodiments are described further below with reference to the drawings. [Brief explanation of the drawing]

[0013] [Figure 1] A flowchart illustrating the lithography patterning process in various embodiments.

[0014] [Figure 2] A simplified diagram of a processing chamber according to a specific embodiment. [Modes for carrying out the invention]

[0015] This specification provides detailed references to specific embodiments of the Disclosure. Examples of specific embodiments are shown in the accompanying drawings. While the Disclosure is described in conjunction with these specific embodiments, it will be understood that the Disclosure is not intended to be limited to such specific embodiments. Rather, the Disclosure is intended to include alternatives, modifications, and equivalents that may fall within its spirit and scope. The following description includes some specific details to provide a full understanding of the Disclosure. The Disclosure may be implemented without some or all of these specific details. In other examples, well-known process operations are not described in detail so as not to make the Disclosure unnecessarily difficult to understand.

[0016] Thin film patterning in semiconductor processing is often a crucial step in semiconductor manufacturing. Patterning involves lithography. In conventional photolithography (such as 193nm photolithography), a chemical reaction occurs in the photoresist when it is exposed to photons in a selected area defined by a photomask. This creates a chemical contrast that can be used in the development process, and specific parts of the photoresist are removed to form a pattern, thus printing the pattern onto the photosensitive photoresist film. The patterned and developed photoresist film can then be used as an etching mask to transfer the pattern onto a substrate film made of metal, oxide, etc.

[0017] Advanced technology nodes (as defined by the International Semiconductor Technology Roadmap), including the 22nm node, 16nm node, and beyond, require continuous improvements in lithography resolution. For example, at the 16nm node, the width of vias or lines in damascene structures is typically around 30nm or less, which is impossible with simple 193nm photolithography or otherwise requires complex multi-patterning methods.

[0018] Extreme ultraviolet (EUV) lithography can expand lithography techniques by moving to image source wavelengths shorter than those achievable with conventional photolithography methods. EUV light sources with wavelengths of approximately 10–20 nm or 11–14 nm (e.g., 13.5 nm) can be used in state-of-the-art lithography tools (also called scanners). Because EUV rays are strongly absorbed by a wide range of solid and liquid materials, including quartz, water vapor, and atmospheric pressure gases, EUV scanners operate in a vacuum.

[0019] EUV lithography utilizes EUV resists that can be patterned using EUV light to form a mask for etching the underlying layer. The EUV resist may be a polymer-based chemically amplified resist (CAR) formed by liquid spin-on technology. An alternative to CAR is a metal oxide-based EUV photoresist (PR) film that can be directly photopatterned. Such PR films may be formed by (wet) spin-on technology and are available from Inpria in Corvallis, Oregon, such as the films described in U.S. Patent Applications US2017 / 0102612 and US2016 / 0116839, which are incorporated herein by reference for disclosures of at least photopatternable metal oxide-containing films, or the dry-deposited films described in PCT Application PCT / US19 / 31618, filed May 9, 2019, entitled METHODS FOR MAKING EUV PATTERNABLE HARD MASKS, which are incorporated herein by reference for disclosures of composition and patterning of metal oxide films that are directly photopatternable to form at least EUV resist masks. These directly photopatternable EUV resists may consist of, or contain, metals with high EUV absorbance, their organometallic oxides / hydroxides, and other derivatives. Upon EUV exposure, EUV photons and the generated secondary electrons are converted into SnO x It can induce chemical reactions such as beta-H removal reactions in metal oxide resists (and other metal oxide resists), providing chemical functions that promote crosslinking and other changes in the resist film. These chemical changes can then be utilized in the development process to selectively remove exposed or unexposed areas of the resist film, forming an etching mask for pattern transfer.

[0020] This disclosure relates to lithographic patterning techniques and materials exemplified by EUV lithography, but it should be understood that it is also applicable to other next-generation lithography techniques. Currently, in addition to EUV with the standard 13.5 nm EUV wavelength in use and development, the radiation sources most relevant to such lithography are DUV (deep ultraviolet), generally referring to the use of excimer laser sources at 248 nm or 193 nm, X-rays (formally including EUV of X-rays in the low-energy range), and electron beams (which may include a wide energy range). The specific method may depend on the specific materials and applications used in the semiconductor substrate and the final semiconductive device. Thus, the methods described in this application are only examples of methods and materials that can be used in this technology.

[0021] The photolithography process typically includes one or more baking steps to facilitate the chemical reactions necessary to create a chemical contrast between the exposed and unexposed areas of the photoresist. Such baking steps are typically carried out based on tracks for high-volume manufacturing (HVM), and the wafers are baked on a hot plate at a predetermined temperature under an atmosphere or, in some cases, under a N2 flow. During these baking steps, not only the baking atmosphere but also the introduction of additional reactive gas components into the atmosphere can be more thoroughly controlled to help further reduce the dose requirements and / or improve the pattern fidelity.

[0022] This disclosure describes a new baking method that includes thorough control of the baking atmosphere and reactive gas introduction, and, in some cases, thorough control of the heating rate of the baking temperature. Such a method may be particularly effective for metal oxide-based EUV photoresists (PRs). Examples of effective reactive gases include water, hydrogen, oxygen, ozone, hydrogen peroxide, carbon monoxide, carbon dioxide, ammonia, nitrous oxide, nitric oxide, methylamine, dimethylamine, alcohol, acetylacetone, formic acid, oxalyl chloride, carboxylic acids, other amines, substituents of these materials, etc. The reactive gas is provided in the gas phase and may be vaporized before being supplied to the reaction chamber. Various exemplary gases are further described below.

[0023] Although the present disclosure is not limited to a specific logic or mechanism of operation, it is understood that these reactive gas molecules can accelerate the crosslinking reaction of the metal oxide-based EUV photoresist in the EUV exposure region (in this example, the region remaining for mask formation following development of the pattern film) by oxidation, coordination, or acid-base chemistry while having a limited effect on crosslinking in the non-exposed region. Alternatively, or in addition, in some cases the reactive gas molecules may further enhance the stability of the resist by promoting the removal of volatile species from the metal oxide-based EUV photoresist.

[0024] Figure 1 shows flowcharts for various embodiments. In operation 101, the resist is deposited on the substrate. The resist-deposited substrate typically contains a base material that is ultimately etched after the resist is patterned / developed. In various embodiments, the resist-deposited substrate may have an exposure layer such as amorphous carbon, spin-on carbon (SoC), spin-on glass (SoG), silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or silicon oxycarbide. Often, the exposure layer is an ashingable hard mask (AHM). The resist deposited in operation 101 is a metal oxide-based EUV photoresist. This deposition may be achieved by wet spin-on techniques or by dry vapor-based techniques such as chemical vapor deposition (CVD) and / or atomic layer deposition (ALD), which may be operated by thermal energy, plasma energy, or both. Next, in operation 103, the substrate is exposed to heat in a first baking step, often called post-coating bake (PAB). In operation 105, the substrate is exposed to EUV rays to pattern the resist, thereby forming exposed and unexposed areas of the resist. Next, in operation 107, the substrate is exposed to heat in a second baking step, often called post-exposure bake (PEB). Next, in operation 109, the resist is developed to selectively remove the unexposed areas. In various embodiments of this specification, the atmosphere to which the substrate is exposed may be controlled during the PAB in operation 103 and / or during the PEB in operation 107. For example, the substrate may be exposed to one or more reaction gases during these steps. Each baking step is described further below. 1. Post-coating bake (PAB)

[0025] Post-coating bake is performed after the resist has been deposited on the substrate and before the resist is exposed to EUV rays for patterning. See operation 103 in Figure 1. PAB may be performed to remove excess solvent (e.g., if the resist was deposited by spin-on method), remove other low molecular weight or volatile species, and promote the desired degree of crosslinking in the resist. These features act to increase the stability of the resist. For example, by removing unbonded or only loosely bonded low molecular weight or volatile species in the resist, the gas release of metal-containing molecules is kept to an acceptable amount (e.g., <1E10 molecules / cm³). 2 This can be reduced to × months). Removing these materials is beneficial because if they are not removed, they can contaminate downstream processes, equipment, and substrates. Crosslinking achieved during PAB also improves resist stability, but too much crosslinking can lead to increased line width roughness. Therefore, crosslinking may be controlled to the desired extent during PAB.

[0026] In various embodiments of this specification, the substrate may be exposed to a reaction gas during PAB. The reaction gas may facilitate the removal of low molecular weight species or volatile species. In various embodiments, the low molecular weight species removed during PAB may have zero metal atoms, one metal atom, or two metal atoms. In some cases, the low molecular weight species removed may include dimetallic species. Molecules having three or more metal atoms typically have relatively heavy molecular weights, are relatively volatile, and may substantially remain in the resist during PAB. In addition to the removal of low molecular weight species, the reaction gas may promote a desired degree of crosslinking in the resist. As a result of these features, the use of a reaction gas in PAB may help stabilize the resist.

[0027] Exemplary processing apparatuses and reaction gases are provided below. In various embodiments, the substrate may be exposed to one or more of these reaction gases during PAB. In certain examples, the substrate may be exposed during PAB to a processing atmosphere having a controlled amount of oxygen and / or moisture (e.g., water vapor) along with an inert gas. In some embodiments, suitable gas sensors and feedback mechanisms may be used to ensure that the components of the processing atmosphere are controlled within a desired range.

[0028] In various embodiments, one or more processing conditions during PAB may be controlled as follows: The substrate may be heated to a high temperature of about 100–170°C (e.g., about 100–130°C in some cases). The pressure may be maintained at about 0.1–760 Torr (e.g., about 0.1–1 Torr in some cases). The substrate may be exposed to the high temperature for about 1–10 minutes (e.g., about 2–5 minutes). An inert gas may be flowed into the processing chamber at a rate of about 10–10,000 sccm. In certain examples, the oxygen (e.g., O2) concentration in the processing chamber may be controlled during PAB. In these or other embodiments, the moisture (e.g., H2O vapor) concentration may be controlled during PAB.

[0029] In some embodiments, PAB may be omitted. For example, if the resist is deposited using a dry vapor-based technique rather than a wet spin-on technique, PAB may not be necessary because there is no need to remove excess solvent used to deposit the resist. However, even when the resist is deposited using a dry vapor-based technique, it may be beneficial to perform PAB to promote the desired degree of crosslinking and to remove low molecular weight or non-volatile species that may be a greater concern with dry vapor-based deposition techniques than with wet spin-on techniques. In some embodiments, PAB may be a conventional PAB; that is, PAB may occur without exposing the substrate to reactive gas species and / or in an uncontrolled atmosphere. In such embodiments, the substrate may be exposed to reactive gas species during a post-exposure bake, which is further described below. 2. Post-exposure bake (PEB)

[0030] Post-exposure baking is performed after the resist has been exposed to EUV rays for patterning and before the resist is developed to remove its unexposed areas. See operation 107 in Figure 1. PEB may be performed for several purposes, for example, 1) to promote the complete evaporation of organic fragments generated during EUV exposure, 2) to oxidize metal hydride species (other products from the beta-H removal reaction during EUV exposure) to metal hydroxides, and 3) to promote bridging between adjacent -OH groups and form a bridging metal oxide network.

[0031] The baking temperature is carefully selected to achieve optimal EUV lithography performance. If the PEB temperature is too low, not only will organic fragments not be removed completely, but crosslinking will be insufficient, resulting in insufficient chemical contrast for development at the desired level. If the PEB temperature is too high, it will lead to adverse effects including severe oxidation and film shrinkage in unexposed areas (in this example, areas removed by development of the pattern film for mask formation), as well as undesirable interdiffusion at the interface between the PR and the underlayer (UL) (usually a spin-on carbon material), both of which will result in reduced chemical contrast and increased defect density due to insoluble debris. Having baking temperature and baking time as the only knobs often severely limits adjustability and process window.

[0032] As described herein, thorough control of the baking atmosphere and the introduction of reaction gas species during the PEB process provides a knob for additional chemicals to fine-tune the crosslinking process. For example, since the exposed region tends to be more polar than the unexposed region due to alkyl group loss and hydride / hydride component formation, the presence of polar and oxidizing molecules such as H2O2 during the baking process can promote the oxidation of metal hydrides in the exposed region. Other gases, as described in the reaction gas section below, may similarly alter the rate of hydride oxidation and hydroxide crosslinking reactions through oxidation, acid-base chemicals, coordination chemicals, and combinations thereof. The reaction gases may be supplied in a controlled atmosphere using, for example, one of the apparatuses described in the baking apparatus section below. The reaction gases may be supplied together with non-reactive gases such as N2, Ar, He, Ne, Kr, and Xe. In some cases, air or clean dry air may be supplied to the atmosphere during PEB.

[0033] The ability to control the rate of crosslinking reactions in metal oxide-based EUV photoresist materials provides a broader process window that allows for further optimization of lithography performance by minimizing interdiffusion and other related defect formation mechanisms. For example, if the reaction gas can efficiently lower the baking temperature requirement, concerns about interdiffusion at the PR / UL interface can be mitigated, which would be beneficial for defect reduction.

[0034] In certain embodiments, one or more processing conditions during PEB may be controlled as follows: The substrate may be heated to a high temperature of about 100–250°C (e.g., about 120–200°C in some cases). The pressure may be maintained at about 0.1–760 Torr (e.g., about 0.1–1 Torr in some cases). The substrate may be exposed to the high temperature for about 1–10 minutes (e.g., about 2–5 minutes). An inert gas may be flowed into the processing chamber at a rate of about 10–10,000 sccm. In certain examples, the oxygen (e.g., O2) concentration in the processing chamber may be controlled during PEB. In these or other embodiments, the moisture (e.g., H2O vapor) concentration may be controlled during PEB.

[0035] In certain embodiments, the substrate may be exposed to ammonia in the PEB. In some cases, ammonia may be the only reaction gas present in the PEB, while in other cases, one or more additional reaction gases may be provided along with the ammonia. In some embodiments, the ammonia may be provided at a concentration of about 0.001–5.0 (vol)%, and in some cases, at atmospheric pressure or at a partial pressure of about 1–100 mTorr, or at a partial pressure of about 1–10 mTorr if the processing chamber is under vacuum, at a concentration of about 0.001–0.5 (vol)%. The duration of the PEB (and / or the duration of substrate exposure to ammonia in the PEB) may be about 5 seconds to about 10 minutes, and in some cases, about 5 seconds to 1 minute. After the substrate has been exposed to ammonia, the processing chamber may be purged with an inert gas. In various embodiments, the purging period with the inert gas may be the same length as the duration of substrate exposure to ammonia, or longer. These steps may accelerate the alkali-catalyzed reaction of M-OH condensation / crosslinking to form relatively high molecular weight, low-volatile species, resulting in a more stable photoresist film as described above. These steps may also cure and densify the film region exposed to EUV rays (or other types of lithography patterning radiation), enabling these effects at a baking temperature lower than that required to achieve the same film properties. In some embodiments, these same reaction conditions may be used in PAB. In some cases, these same reaction conditions may be used in PAB and / or PEB with alternative or additional reaction gases described herein, including but not limited to other volatile amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, and pyridine.

[0036] In some embodiments, the PEB may be a conventional PEB; that is, the PEB may be carried out without providing a reaction gas to the substrate and / or in an uncontrolled atmosphere. In such cases, one or more reaction gases may be provided to the substrate during the PAB. 3. Reaction gas

[0037] In various embodiments of the present specification, the substrate may be exposed to one or more reactive gases during the photoresist baking operation. As described above, the reactive gas may promote the desired degree of crosslinking, promote the removal of low molecular weight species or volatile species, and / or stabilize the photoresist.

[0038] Several different reactive gases may be used. Examples of effective reactive gases are water (H2O), hydrogen (H2), oxygen (O2), ozone (O3), hydrogen peroxide (H2O2), carbon monoxide (CO), carbon dioxide (CO2), ammonia (NH3), nitrous oxide (N2O), nitric oxide (NO), methylamine (CH3NH2), dimethylamine ((CH3)2NH), trimethylamine (N(CH3)3), ethylamine (CH3CH2NH2), diethylamine ((CH3CH2)2NH), triethylamine (N(CH2CH3)3), alcohol (C n H 2n+1 OH (including but not limited to methanol, ethanol, propanol, and butanol)), acetylacetone (CH3COCH2COCH3), formic acid (HCOOH), oxalyl chloride ((COCl)2), carboxylic acid (C n H 2n+1 COOH), and other small molecule amines (NR 1 R 2 R 3 (R 1 、R 2 、R 3 are each independently selected from hydrogen, hydroxyl, aliphatic, haloaliphatic, haloheteroaliphatic, heteroaliphatic, aromatic, aliphatic aromatic, heteroaliphatic aromatic, or combinations thereof)), etc. Substituted forms of these reactive gases may also be used. In some cases, the substrate may be exposed to two or more reactive gases during the photoresist baking operation.

[0039] The reaction gas may interact with the photoresist by oxidation, coordination, or by acid-base chemicals. If the reaction gas is supplied during PEB operation, it may preferentially interact with the photoresist in the region exposed to EUV rays. This preferential interaction may result from chemical changes occurring during EUV exposure (e.g., loss of alkyl groups in the photoresist).

[0040] Following the substrate's exposure to the reaction gases in the PAB and / or PEB, the chamber in which the substrate is processed may be evacuated and / or purged with, for example, an inert gas. In some cases, the inert gas purging period may be at least the same length as the period during which the substrate is exposed to the reaction gases. 4. Temperature gradient

[0041] In some embodiments, the rate at which the substrate temperature changes may be controlled during the baking process. In some cases, rapid heating and rapid cooling can be problematic. By controlling the rate at which the substrate temperature rises and falls, problems related to rapid heating and rapid cooling can be avoided. Furthermore, the rate at which the baking temperature rises and / or falls may be controlled to fine-tune the crosslinking reaction in the resist. 5. Baking equipment

[0042] The baking operations described herein may occur in various different types of processing apparatus. In some cases, the processing apparatus may have a sealed chamber that is isolated from the surrounding environment. In other cases, the processing apparatus may have an open chamber that is not isolated from the surrounding environment. In certain cases where an open chamber is used, the substrate may be processed based on a track that can operate continuously or discontinuously. Generally, a sealed chamber provides better control over the processing atmosphere and offers greater safety from potentially hazardous reactive chemicals. However, an open chamber may be preferred, for example, when non-toxic chemicals are used in mass production.

[0043] The chamber may have one or more inlets to provide a desired processing atmosphere. The desired processing atmosphere may contain one or more reaction gases as described above. The inlets may be fluidly connected to a reaction gas source. The reaction gases may flow from the reaction gas source through a gas supply line and into the chamber through the inlets. If the reaction gases are liquids at a suitable temperature, they may be stored as liquids and vaporized before being supplied to the gas supply line / inlets / chamber. In certain embodiments, air and / or inert gases (e.g., N2, Ar, He, Ne, Kr, Xe, etc.) may also be provided to the processing atmosphere. These, too, may flow from a gas source through a gas supply line and into the chamber through the inlets. In some cases, the processing atmosphere may not contain air.

[0044] The chamber may also include one or more outlets for removing material from the chamber. The outlets may be fluidly connected to a vacuum source to allow active removal of gas species from the chamber. Vacuum-connected outlets may be used in both closed and open chambers. When used in a closed chamber, the vacuum-connected outlets may be capable of processing at near-atmospheric pressure. If the processing chamber is an open chamber that is not sealed from the surroundings, the outlets may be pathways through which gas can passively escape from the chamber.

[0045] As described above, in certain embodiments, the atmosphere within the chamber may be controlled during the baking process. In some cases, the concentration of the reaction gas (e.g., oxygen and / or water and / or other reaction gases described herein) may be actively controlled during the baking process. In addition to the inlet and outlet described above, the chamber may further be equipped with sensors (e.g., residual gas analyzers, Fourier transform infrared spectrometers, etc.) to monitor the composition of its atmosphere. These sensors may be used to provide feedback for actively controlling the composition of the baking atmosphere.

[0046] To bake the photoresist, the chamber comprises one or more heating elements configured to heat the substrate. The heating elements may heat the substrate from above and / or below. The heating elements may heat the front side of the substrate (e.g., where the semiconductor device / structure is formed) and / or the back side of the substrate. Various different types of heating elements may be used individually or in combination with each other. Examples of heating elements may include heating substrate supports (e.g., bases, chucks, etc.) and radiation sources such as infrared lamps and / or ultraviolet lamps.

[0047] In some embodiments, the chamber may include one or more cooling elements configured to cool the substrate. For example, the substrate support may be configured to cool the substrate. In one embodiment, the substrate support may include a cooling channel through which a heat exchange fluid flows to cool the substrate. Other heat exchange devices may be used as needed for specific applications. The cooling elements may be particularly effective in controlling the rate at which the substrate cools after the baking operation.

[0048] The chamber may also include temperature sensors for monitoring the temperature of the substrate and / or substrate support during the baking operation. In one example, the chamber includes a pyrometer for measuring the temperature of the substrate surface during baking. Temperature readings from the pyrometer or other temperature sensors may be used as feedback to actively control the substrate temperature during baking.

[0049] Figure 2 shows a simplified diagram of a processing chamber 200 according to one embodiment. In this example, the processing chamber 200 is a sealed chamber with a controllable atmosphere. The substrate 201 may be placed on a substrate support 202 which can also heat and / or cool the substrate. Alternative or additional heating and cooling elements may be provided. The processing gas enters the processing chamber 200 through an inlet 203. The material is removed from the processing chamber 200 through an outlet 204 which may be connected to a vacuum source (not shown). The operation of the processing chamber 200 may be controlled by a controller 206, which will be further described below. Furthermore, a sensor 205 may be provided, for example, to monitor the temperature and / or composition of the atmosphere in the processing chamber 200. Values ​​from the sensor 205 may be used by the controller 206 in an active feedback loop.

[0050] The baking chamber may be configured in several forms. In some embodiments, this chamber is the same as the chamber used for depositing photoresist, and / or the same as the chamber used for exposing photoresist to EUV rays, and / or the same as the chamber used for developing photoresist. In some embodiments, this chamber is a dedicated baking chamber not used for other processes such as deposition, etching, EUV exposure, or photoresist development. This chamber may be a standalone chamber or may be integrated with larger processing tools, such as a deposition tool used for depositing photoresist, an EUV exposure tool used for exposing photoresist to EUV rays, and / or a developing tool used for developing photoresist. The baking chamber may be combined with one or more of these tools as needed for a particular application.

[0051] The chamber may include a controller. In some embodiments, the control device is part of a system which may be part of the examples described above. Such a system may include a semiconductor processing apparatus comprising a processing tool, a chamber, a processing platform, and / or specific processing components (such as a wafer pedestal, a gas flow system, etc.). These systems may be integrated with electronic equipment for controlling pre-processing, processing, and post-processing operations of semiconductor wafers or substrates. These electronic equipment may be referred to as “controllers” and may control various components or sub-components of the system. Depending on the processing requirements and / or the type of system, the controller may be programmed to control any of the processes disclosed herein, including the supply of processing gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid supply settings, position operation settings, tools and other transport tools connected to or coupled to a particular system, and / or wafer loading and unloading to a load lock.

[0052] Generally, a controller may be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive and issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. An integrated circuit may include a firmware-type chip that stores program instructions, a chip defined as a digital signal processor (DSP), an application-specific integrated circuit (ASIC), and / or one or more microprocessors or microcontrollers that execute program instructions (e.g., software). Program instructions are instructions that are transmitted to the controller in the form of various individual settings (or program files) and may define operating parameters for executing a particular process on or for a semiconductor wafer or for a system. In some embodiments, the operating parameters may be part of a recipe defined by a process engineer to realize one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or one or more processing steps during the manufacturing of a wafer die.

[0053] In some embodiments, the controller may be part of a computer integrated with or coupled to the system, or otherwise networked to the system, or a combination thereof, or coupled to such a computer. For example, the controller may reside in a “cloud” enabling remote access to wafer processing, or may be all or part of a fab host computer system. The computer may enable remote access to the system to monitor the progress of manufacturing operations, review the history of past manufacturing operations, examine trends or performance criteria from multiple manufacturing operations, modify parameters of the current operation, set up subsequent processing steps for the current operation, or start a new process. In some examples, a remote computer (e.g., a server) may provide process recipes to the system via a network that may include a local network or the internet. The remote computer may include a user interface that enables the entry or programming of parameters and / or settings that are then transmitted from the remote computer to the system. In some examples, the controller receives instructions in the form of data that specify the parameters of each processing step performed during one or more operations. It should be understood that the parameters may be specific to the type of process being performed and the type of tool that the controller is coupled to or configured to control. Therefore, as described above, the controllers may be distributed by, for example, including one or more separate controllers that are networked together and by cooperating toward a common purpose, such as the processes and controls described herein. An example of controllers distributed toward such a purpose would be one or more integrated circuits on a chamber that are located remotely (for example, at the platform level or as part of a remote computer) and communicate with one or more integrated circuits that cooperate to control the processes in the chamber.

[0054] Rather than being limiting, the exemplary systems may include plasma etching chambers or modules, deposition chambers or modules, spin rinse chambers or modules, metal plating chambers or modules, cleaning chambers or modules, bevel edge etching chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, ALD chambers or modules, atomic layer etching (ALE) chambers or modules, ion implantation chambers or modules, track chambers or modules, and other semiconductor processing systems that may be related to or used in the fabrication and / or manufacture of semiconductor wafers.

[0055] As described above, the controller may communicate with one or more of the following, depending on the processing steps performed by the tool: other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools installed throughout the factory, a main computer, another controller, or tools used for material handling to load and unload wafer containers to and from tool locations and / or load ports in a semiconductor manufacturing plant. conclusion

[0056] A baking method for improving the EUV lithography performance of metal-containing EUV resists is disclosed.

[0057] The examples and embodiments described herein are for illustrative purposes only, and it will be understood that various modifications or changes in that regard will be suggested to those skilled in the art. Various details have been omitted for clarity, but various conceptual changes may be made. Thus, these examples should be considered illustrative rather than restrictive, and this disclosure should not be limited to the details described herein, although it may be modified within the scope of this disclosure.

Claims

1. A method for baking a photoresist layer on a substrate, The substrate is received into the processing chamber, the substrate has a photoresist layer thereon, and the photoresist layer contains a metal-containing photoresist material. A reaction gas species is introduced from a gas source through a gas supply line to the processing chamber, and the substrate is exposed to the reaction gas species within the processing chamber. Baking the photoresist layer while the substrate is exposed to the reaction gas species, A method that includes [a certain feature].

2. The method according to claim 1, The method wherein the photoresist layer comprises an extreme ultraviolet (EUV) photoresist material.

3. The method according to claim 2, The method wherein the reaction gas species comprises a gas selected from the group consisting of water, hydrogen, oxygen, ozone, hydrogen peroxide, carbon monoxide, carbon dioxide, ammonia, nitrous oxide, nitric oxide, alcohol, acetylacetone, formic acid, oxalyl chloride, pyridine, carboxylic acid, amine, and combinations thereof.

4. The method according to claim 3, The method wherein the reaction gas species includes water.

5. The method according to claim 3, The method wherein the reaction gas species includes hydrogen.

6. The method according to claim 3, The method wherein the reaction gas species includes the oxygen.

7. The method according to claim 3, The method wherein the reaction gas species includes the ozone.

8. The method according to claim 3, The method wherein the reaction gas species includes hydrogen peroxide.

9. The method according to claim 3, The method wherein the reaction gas species includes carbon monoxide.

10. The method according to claim 3, The method wherein the reaction gas species includes carbon dioxide.

11. The method according to claim 3, The method wherein the reaction gas species includes the ammonia.

12. The method according to claim 11, Baking the photoresist occurs after the photoresist has been exposed to EUV rays for patterning, provided that one of the following conditions is met: (i) The processing chamber is maintained at atmospheric pressure while the photoresist is being baked, and the ammonia is provided at a concentration of about 0.001 to 5% (vol). (ii) The processing chamber is maintained at near-atmospheric pressure while the photoresist is being baked, and the ammonia is supplied at a partial pressure of about 1 to 100 mTorr.

13. The method according to claim 3, A method wherein the reaction gas species includes the nitrous oxide and / or nitric oxide.

14. The method according to claim 3, The method wherein the reaction gas species includes the alcohol.

15. The method according to claim 3, The method wherein the reaction gas species includes acetylacetone.

16. The method according to claim 3, The method wherein the reaction gas species includes the formic acid.

17. The method according to claim 3, The method wherein the reaction gas species includes oxalyl chloride.

18. The method according to claim 3, The method wherein the reaction gas species includes the carboxylic acid.

19. The method according to claim 3, The method wherein the reaction gas species includes the amine.

20. The method according to claim 19, The method wherein the amine includes methylamine, dimethylamine, and / or trimethylamine.

21. The method according to claim 19, The method wherein the amine includes ethylamine, diethylamine, and / or triethylamine.

22. A method according to any one of claims 2 to 21, The method wherein the reaction gas species is oxidizing.

23. A method according to any one of claims 2 to 22, The method wherein the reaction gas species has polarity.

24. A method according to any one of claims 2 to 23, A method for exposing the substrate to the reaction gas species to promote crosslinking in the photoresist layer.

25. A method according to any one of claims 2 to 24, Exposing the substrate to the reaction gas species is a method for improving the stability of the photoresist layer.

26. A method according to any one of claims 2 to 25, A method for exposing the substrate to the reaction gas species, thereby promoting the removal of low molecular weight species within the photoresist layer.

27. The method according to claim 26, The method wherein the low molecular weight species comprises zero, one, or two metal atoms per molecule.

28. A method according to any one of claims 2 to 27, A method for exposing the substrate to the reaction gas species, wherein the metal hydride species in the photoresist layer are oxidized to metal hydroxide species.

29. A method according to any one of claims 2 to 28, further, A method comprising applying a vacuum to the processing chamber while baking the photoresist layer.

30. A method according to any one of claims 2 to 29, further, A method comprising controlling the moisture concentration in the processing chamber to remain within a target moisture concentration range while the photoresist layer is being baked.

31. A method according to any one of claims 2 to 30, further, A method comprising controlling the oxygen concentration in the processing chamber to remain within a target oxygen concentration range while the photoresist layer is being baked.

32. A method according to any one of claims 2 to 31, A method wherein the processing chamber is maintained below atmospheric pressure while the photoresist layer is being baked.

33. The method according to claim 32, A method wherein the processing chamber is maintained at a pressure below atmospheric pressure while the photoresist layer is being baked.

34. A method according to any one of claims 2 to 33, further, A method comprising increasing the temperature of a substrate support on which the substrate is mounted while baking the photoresist layer.

35. A method according to any one of claims 2 to 34, further, A method comprising lowering the temperature of a substrate support on which the substrate is mounted while baking the photoresist layer.

36. A method according to any one of claims 2 to 35, further, A method comprising controlling the flow of the reaction species into the processing chamber in order to achieve a target degree of crosslinking.

37. A method according to any one of claims 2 to 36, A method for baking the photoresist layer, comprising heating the substrate on a hot plate.

38. A method according to any one of claims 2 to 37, A method comprising baking the photoresist layer by exposing the substrate to infrared and / or ultraviolet light.

39. A method according to any one of claims 2 to 38, A method for baking the photoresist layer, comprising heating the substrate from above.

40. A method according to any one of claims 2 to 39, A method for baking the photoresist layer, comprising heating the substrate from below.

41. A method according to any one of claims 2 to 40, A method wherein the photoresist layer is not patterned even after being applied to the substrate, and the baking is performed as post-coating bake (PAB).

42. A method according to any one of claims 2 to 41, The photoresist layer is coated onto the substrate and patterned by partial exposure to EUV rays, resulting in exposed and unexposed portions of the photoresist layer, and the baking is post-exposure bake (PEB), in this method.

43. The method according to claim 42, The method wherein the reaction gas species includes polar and oxidizing molecules.

44. The method according to claim 43, The method wherein the reaction gas species includes hydrogen peroxide.

45. An apparatus for baking a photoresist layer on a substrate, Processing chamber and The processing chamber includes an inlet for introducing a reaction gas species, An outlet for removing material from the processing chamber, The substrate support in the processing chamber, A heater configured to heat the substrate by conduction, convection, and / or radiation, A controller having at least one processor, wherein the at least one processor is configured to control the device to perform any of the methods of claims 1 to 44. A device equipped with the following features.

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