Oxidation treatment of positive photoresist film

Abstract

To provide a method for depositing a positive photoresist using a dry deposition and oxidation process.SOLUTION: A method of forming a photoresist layer on a substrate in a vacuum chamber includes providing a metal precursor vapor in the vacuum chamber. The method further comprises providing an oxidant vapor in the vacuum chamber, wherein a reaction between the metal precursor vapor and the oxidant vapor results in the formation of a positive photoresist layer on the surface of the substrate. The positive photoresist layer is a metal oxo-containing material. The method further comprises performing a post-annealing treatment of the metal oxo-containing material in an oxygen-containing environment.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 17 / 684,329, filed March 1, 2022, which claims the benefit of U.S. Provisional Application No. 63 / 244,504, filed September 15, 2021, and U.S. Provisional Application No. 63 / 165,646, filed March 24, 2021, the entire contents of which are incorporated herein by reference.

[0002] Field FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate to the field of semiconductor processing, and more particularly to a method for depositing a positive photoresist layer on a substrate using dry deposition and oxidation processes. [Background technology]

[0003] 2. Description of Related Art Lithography has been used for decades in the semiconductor industry to create 2D and 3D patterns for microelectronic devices. The lithography process involves spin-on deposition of a film (photoresist), irradiating the film in a selected pattern with an energy source (exposure), and removing (etching) the exposed (positive tone) or unexposed (negative tone) areas of the film by dissolving them in a solvent. A bake is then performed to drive off any remaining solvent.

[0004] Photoresist must be a radiation-sensitive material, and upon irradiation, a chemical transformation occurs in the exposed portions of the film, allowing for a change in solubility between the exposed and unexposed areas. This change in solubility is used to remove (etch) either the exposed or unexposed areas of the photoresist. The photoresist is then developed, and the pattern can be transferred by etching into the underlying thin film or substrate. After the pattern is transferred, the remaining photoresist is removed, and this process can be repeated multiple times to obtain 2D and 3D structures used in microelectronic devices.

[0005] Several properties are important in lithography processes. These properties include sensitivity, resolution, low line edge roughness (LER), etch resistance, and the ability to form thinner layers. The higher the sensitivity, the lower the energy required to change the solubility of the as-deposited film. This increases the efficiency of the lithography process. Resolution and LER determine how narrow features can be achieved by the lithography process. Pattern transfer to form deep structures requires more etch-resistant materials. More etch-resistant materials also allow for thinner films. Thinner films increase the efficiency of the lithography process. Summary of the Invention

[0006] Embodiments disclosed herein include methods for depositing positive photoresist using a dry deposition and oxidation treatment process.

[0007] In one embodiment, a method for forming a photoresist layer on a substrate in a vacuum chamber includes providing a metal precursor vapor in the vacuum chamber. In one embodiment, the method further includes providing an oxidizer vapor in the vacuum chamber, where a reaction between the metal precursor vapor and the oxidizer vapor forms a positive photoresist layer on the surface of the substrate, the positive photoresist layer being a metal-oxo-containing material. In one embodiment, the method further includes performing a post-annealing treatment of the metal-oxo-containing material in an oxygen-containing environment.

[0008] In one embodiment, a method for forming a photoresist layer on a substrate in a vacuum chamber includes providing a metal precursor vapor in the vacuum chamber. In one embodiment, the method further includes providing an oxidizer vapor in the vacuum chamber, where a reaction between the metal precursor vapor and the oxidizer vapor results in atomic layer deposition (ALD) of a positive photoresist layer on the surface of the substrate, the positive photoresist layer being a metal-oxo-containing material. In one embodiment, the method further includes performing a post-annealing treatment of the metal-oxo-containing material in an oxygen-containing environment.

[0009] In one embodiment, a method for forming a photoresist layer on a substrate in a vacuum chamber includes providing a metal precursor vapor in the vacuum chamber. In one embodiment, the method further includes providing an oxidizer vapor in the vacuum chamber, where a reaction between the metal precursor vapor and the oxidizer vapor results in a positive photoresist layer being deposited on the surface of the substrate, the positive photoresist layer being a metal-oxo-containing material. In one embodiment, the method further includes annealing the positive photoresist layer in an oxygen-containing environment based on an ozone (O3) source gas. In one embodiment, the method further includes exposing a portion of the positive photoresist layer to an extreme ultraviolet (EUV) energy source. In one embodiment, the method further includes developing the positive photoresist layer using a basic developer. [Brief explanation of the drawings]

[0010] [Figure 1] 1A-1C illustrate cross-sectional views depicting various operations in a patterning process using a positive photoresist material formed by the process described herein, according to one embodiment of the present disclosure. [Figure 2A] Included are general formulas and specific examples of metal precursors suitable for use in producing positive tone photoresist films according to one embodiment of the present disclosure. [Figure 2B] 1 illustrates an amine that can be used as a developer for a positive photoresist, according to one embodiment of the present disclosure. [Figure 3] FIG. 1 is a cross-sectional view of a processing tool that may be used to perform the dry deposition and oxidation treatment processes described herein, according to one embodiment of the present disclosure. [Figure 4] 1 illustrates a cross-sectional view of a processing tool for depositing a positive photoresist layer on a substrate using a dry deposition and oxidation treatment process according to one embodiment of the present disclosure. [Figure 5] 1 illustrates a close-up view of an edge portion of a movable column of a processing tool for depositing a positive photoresist layer on a substrate by a dry deposition and oxidation treatment process according to one embodiment of the present disclosure. [Figure 6A] FIG. 10 illustrates a close-up view of an edge of a movable column in a processing tool, where the shadow ring is not engaged with the edge ring, in accordance with one embodiment of the present disclosure. [Figure 6B] FIG. 10 is a close-up view of an edge of a movable column in a processing tool, where a shadow ring is engaged with an edge ring, in accordance with one embodiment of the present disclosure. [Figure 7A] 1 illustrates a cross-sectional view of a processing tool for depositing a positive photoresist layer on a substrate using a dry deposition and oxidation treatment process according to one embodiment of the present disclosure. [Figure 7B] FIG. 1 illustrates a cross-sectional view of a processing tool with the pedestal removed to expose a channel in the base plate according to one embodiment of the present disclosure. [Figure 8] 1 illustrates a block diagram of an exemplary computer system according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Described herein is a method for depositing a positive photoresist on a substrate using a dry deposition and oxidation treatment process. In the following description, numerous specific details are set forth, such as chemical vapor deposition (CVD) and atomic layer deposition (ALD) processes, material schemes for depositing the positive photoresist, etc., in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known aspects, such as integrated circuit fabrication, have not been described in detail in order to avoid unnecessarily obscuring embodiments of the present disclosure. Furthermore, it should be understood that the various embodiments illustrated in the figures are illustrative representations and are not necessarily drawn to scale.

[0012] To provide some background, photoresist systems used in extreme ultraviolet (EUV) lithography suffer from low efficiency. Existing photoresist material systems for EUV lithography require high doses to provide the solubility switch necessary to enable development of the photoresist material. Traditionally, carbon-based films known as organic chemically amplified photoresists (CARs) have been used as photoresists. However, more recently, organic-inorganic hybrid materials (metal-oxo) have been used as photoresists for extreme ultraviolet (EUV) radiation. Such materials typically contain metals (e.g., Sn, Hf, Zr), oxygen, and carbon. The transition from deep ultraviolet (DUV) to EUV in the lithography industry has facilitated narrow features with high aspect ratios. Metal-oxo-based organic-inorganic hybrid materials have been shown to exhibit lower line edge roughness (LER) and higher resolution, which are necessary for forming narrow geometries. Furthermore, such films have higher sensitivity and etch resistance, allowing them to be implemented to fabricate relatively thin films.

[0013] Currently, metal-oxo photoresists are deposited by a spin-on method involving wet chemistry. A post-baking process is required to remove residual solvent from the film and stabilize the film. Additionally, wet methods can generate a large amount of wet waste, which the industry wants to move away from. Photoresist films deposited by spin-on methods often suffer from non-uniformity issues. In accordance with embodiments of the present disclosure, a vacuum deposition process for metal-oxo positive photoresists is described herein that addresses one or more of the above-mentioned problems.

[0014] According to one or more embodiments of the present disclosure, a dry deposition and oxidation process approach for forming a positive photoresist film is described. In some embodiments, thermal chemical vapor deposition (CVD) is used for the dry deposition of the positive photoresist film. In other embodiments, plasma enhanced chemical vapor deposition (PECVD) is used for the dry deposition of the positive photoresist film. In one embodiment, the dry deposition process is not a condensation process. In another embodiment, the dry deposition process is a condensation process. In one embodiment of such a condensation process, the wafer / substrate is maintained at a temperature at which the metal precursor can condense. Precursor condensation can be achieved by maintaining the wafer temperature below the precursor ampoule temperature.

[0015] FIG. 1 shows cross-sectional views illustrating various operations in a patterning process using a positive photoresist material formed by the process described herein, according to one embodiment of the present disclosure.

[0016] Referring to part (a) of FIG. 1, a starting structure 100 includes a positive photoresist layer 104 on a substrate or underlayer 102. In one embodiment, the positive photoresist layer 104 is deposited using dry deposition. Referring to part (b) of FIG. 1, selected locations of the starting structure 100 are irradiated 106 to form an irradiated photoresist layer 104A having irradiated regions 105B and non-irradiated regions 105A. Referring to part (c) of FIG. 1, a removal or etching process 108 is used to provide a developed photoresist layer in the non-irradiated regions 105B. Referring to part (d) of FIG. 1, an etching process 110 using the non-irradiated regions 105B as a mask is used to pattern the substrate or underlayer 102 to form a patterned substrate or patterned underlayer 102A including etched features 112.

[0017] Referring again to Figure 1, the positive photoresist 104 is a radiation-sensitive material that, when irradiated, undergoes a chemical change in the exposed portions of the film, resulting in a change in solubility between the exposed and unexposed areas. This change in solubility is used to remove (etch) the exposed areas of the positive photoresist. The positive photoresist is then developed, and the pattern can be transferred into an underlying thin film or substrate by etching. After the pattern is transferred, the remaining positive photoresist is removed. This process can be repeated multiple times to fabricate 2D and 3D structures, for example, for use in microelectronic devices.

[0018] To provide some background, the lithography industry is accustomed to working with positive photoresist (PR) materials. However, most metal-metal-oxo PR materials are negative photoresists. Positive photoresists offer advantages over negative photoresists, such as higher resolution, better dry etch resistance, and higher contrast. According to one or more embodiments of the present disclosure, methods for fabricating positive PR materials via dry deposition techniques, such as chemical vapor deposition (CVD) and atomic layer deposition (ALD), are described.

[0019] In one embodiment, a Sn precursor is used in the vacuum deposition process of Sn-oxo PR materials. SnOC films can be attractive photoresist films due to their high sensitivity to light exposure. Typically, tin-oxo photoresist films contain Sn-O and Sn-C bonds within the SnOC network. Upon exposure (e.g., UV / EUV), the Sn-C bonds are broken, reducing the carbon content in the film. This can lead to selective etching during the development process. Sn-C can be incorporated into the film by using a metal precursor with Sn-C bonds. In one embodiment, the precursors described herein have Sn-C (where R contains a C bonded to Sn) for exposure sensitivity and a ligand (L) that reacts with an oxidizing agent (e.g., water) to form a photoresist film. In one embodiment, the reactivity between the precursor and the oxidizing agent can be adjusted by modifying the R and / or L of the Sn precursor. Sensitivity can also be adjusted by modifying the R group of the precursor. In one embodiment, indium-oxo or tin-indium-oxo films can also be used as positive-tone photoresist films. The approach described herein can be extended to many other metal-containing films.

[0020] According to one embodiment of the present disclosure, positive photoresists are fabricated using specific types of R groups in metal precursors or plasma-assisted deposition. As an example, a Sn precursor containing a phenyl group (R) (PhSn(NMe2)3) can be used. After exposing the resist to UV light under ambient conditions, FTIR revealed acid moieties in the exposed areas. The resist was then immersed in an aqueous solution of sodium hydroxide (NaOH), and the resist was developed as a positive resist. The acidic portions of the resist (exposed areas) react with the basic NaOH and dissolve in aqueous media to produce a positive resist. Additionally, positive resists were obtained using Sn(nBu)4 in PECVD. Thus, an approach for fabricating positive photoresists is described herein.

[0021] In the first aspect, R groups with low radical stability are used. For example, R groups such as phenyl, alkenyl, and methyl have low radical stability (Sn-C → Sn + C). Figure 2A includes general formulas and specific examples of metal precursors suitable for use in producing positive photoresist films according to one embodiment of the present disclosure. In one embodiment, the two specific examples on the left can be used with thermal CVD, while the two on the right may require PECVD using the development process described below.

[0022] It should be noted that the lithography industry is generally accustomed to working with positive-tone PRs, and almost all new metal-oxo PRs are negative-tone PRs. Positive-tone PRs have advantages over negative-tone PRs, such as higher resolution, better dry etching resistance, and higher contrast. However, for a metal-oxo PR to function as a positive-tone PR, oxidation may be required during or after exposure. Here, we describe a method for fabricating a positive-tone PR using an oxidation operation. It should be understood that the same or similar methods can be used to fabricate a negative-tone PR as well.

[0023] In a second aspect, with respect to the exposure environment, when the photoresist is exposed by an energy source (such as EUV), the exposure chamber (environment) may contain oxygen or may be inert. In one embodiment, the exposure is performed under vacuum using an oxygen source such as O, HO, CO, CO, NO, or NO. In one embodiment, the EUV exposure followed by oxygen exposure may be repeated between 1 and 100 times.

[0024] In a third aspect, the post-annealing is performed in an oxygen-containing environment. In one embodiment, the oxygen source is O3, NO2, NO, or O2, which may be used to form a plasma and / or may be used in conjunction with N2, Ar, or He. In one embodiment, the post-annealing is performed at a temperature in the range of 25-200 degrees Celsius. In one embodiment, the post-annealing is performed at a pressure less than 200 torr. In a specific embodiment, the post-annealing is performed using ozone (O3) as the oxygen source gas, at a temperature in the range of 25-250 degrees Celsius, and at a pressure less than 200 torr.

[0025] In a fourth aspect, basic developers that can be used include inorganic bases that can be prepared in water and whose concentration and development time can be adjusted. In one embodiment, Group 1 and Group 2 hydroxides (e.g., NaOH, KOH), NH4OH, NaHCO3, NaCO3, N(CH3)4OH, or the amines shown in Figure 2B can be used.

[0026] In one embodiment, the oxidant co-reactant is selected from the group consisting of water, O, N, O, NO, CO, CO, ethylene glycol, alcohols (methanol, ethanol, etc.), peroxides (e.g., H0), and acids (formic acid, acetic acid, etc.).

[0027] In a first approach according to one embodiment of the present disclosure, a chemical vapor deposition (CVD) method for forming a positive photoresist involves: (A) evaporating one or more metal precursors (see FIG. 2A) and one or more oxidizers listed above into a vacuum chamber where a substrate wafer is maintained at a predetermined substrate temperature. The substrate temperature can be varied from 0°C to 500°C. As the precursors / oxidizers evaporate in the chamber, they can be diluted with an inert gas such as Ar, N2, or He. Due to the reactivity of the precursors and oxidizers, a metal-oxo film is deposited on the wafer. Evaporation into the chamber can be performed by either simultaneously pulsing all precursors or by alternating between pulsing the metal precursor and the oxidizer. This process can be described as thermal CVD. (B) A plasma can also be turned on during this process, in which case the process can be described as plasma-enhanced (PE)-CVD. Examples of plasma sources include CCP, ICP, remote plasma, and microwave plasma. (C) Deposition of a photoresist film can be achieved by plasma treatment after thermal deposition. In this case, the film is thermally deposited, followed by a plasma treatment operation. The plasma treatment can include a plasma from an inert gas such as Ar, N2, or He, or these gases can be mixed with O2, CO2, CO, NO, NO2, or HO. The treatment can be performed cyclically, with a thermal deposition followed by a plasma treatment and the cycle repeated, or a single plasma treatment performed after completing the deposition portion (post-treatment). PECVD followed by a plasma treatment is also possible. In either case, in one embodiment, a post-annealing is performed in an oxygen-containing environment. In one embodiment, the post-annealing is performed using ozone (O3) as the oxygen source gas, at a temperature in the range of 25-250 degrees Celsius, and at a pressure below 200 torr.

[0028] In a second approach according to one embodiment of the present disclosure, an atomic layer deposition (ALD) process for forming a positive photoresist involves (A) evaporating a metal precursor (see FIG. 2A) into a vacuum chamber where a substrate wafer is maintained at a predetermined substrate temperature. The substrate temperature can be varied between 0 and 500°C. Next, a gas-to-gas purge is performed to remove by-products and excess metal precursor. Next, one or more oxidizers are evaporated into the chamber. The oxidizer reacts with the metal precursor absorbed on the surface. An inert gas purge is then applied to remove by-products and unreacted oxidizer. This cycle can be repeated until the desired thickness is achieved. As the precursor or oxidizer evaporates in the chamber, it can be diluted with an inert gas such as Ar, N2, or He. This process can be described as thermal ALD. Using this method, multiple metals can be incorporated into the film by incorporating additional metal precursor pulses into the ALD cycle. Alternatively, another oxidizer can be pulsed after the first oxidizer. (B) A plasma can be turned on during the oxidizer pulse, and the process can be described as PE-ALD. (C) Deposition can also be performed by thermal ALD followed by a plasma treatment. In this case, thermal deposition is followed by a plasma treatment. The plasma treatment can include a plasma from an inert gas such as Ar, N2, or He, which can be mixed with O2, CO2, CO, NO, NO2, or HO. This process can be performed cyclically: X thermal ALD cycles (X = 1-5000) followed by a plasma treatment, with the entire cycle repeated as many times as needed, or a single plasma treatment performed after completing the deposition part. PE-ALD followed by a plasma treatment is also possible. In either case, in one embodiment, a post-annealing is performed in an oxygen-containing environment. In one embodiment, the post-annealing is performed using ozone (O3) as the oxygen source gas, at a temperature in the range of 25-250 degrees Celsius, and at a pressure below 200 torr.

[0029] In a third approach, according to one embodiment of the present disclosure, atomic layer deposition (ALD) or chemical vapor deposition (CVD) processes for forming positive photoresists involve creating a compositional gradient across the film. For example, the first few nanometers of the film have a different composition than the rest of the film. While the main portion of the film can be optimized for dose, targeting a different composition near the interface layer can improve defectivity, adhesion, sensitivity to EUV photons, sensitivity to chemical reactions to improve post-lithography profile control (especially smearing), and resist disintegration / liftoff. The gradient may be optimized depending on the type of pattern. For example, pillars may require improved adhesion, while line / space patterns may require reduced adhesion for improved dose.

[0030] In one embodiment, the photoresist film deposition method described herein is a vacuum deposition method that does not involve wet chemistry. The positive photoresists described herein have advantages over negative photoresists, such as higher resolution, higher dry etch resistance, and higher contrast.

[0031] An advantage of implementing one or more of the approaches described herein is that the deposition approach for positive photoresist films is a dry deposition approach and does not require wet chemical reactions. Wet chemical methods can generate a large amount of wet by-products, which may be desirable to avoid. Furthermore, spin-on (wet) processes often cause non-uniformity issues, which can be successfully addressed by the vacuum deposition methods described herein. Vacuum deposition also allows for tailoring of the metal and carbon (C) ratios in the film. In spin-on processes, the metal and C ratios are often fixed for a given deposition system. Precursors used to deposit positive photoresist films under vacuum must be volatile, and the precursors described herein are volatile based on their L and R structures. Dry deposition methods may require lower temperatures than other vacuum deposition methods, such as ALD and CVD. Performing deposition at low temperatures can retain a relatively large amount of carbon in the film, which is beneficial for patterning.

[0032] In one embodiment, the vacuum deposition process relies on a chemical reaction between a metal precursor and an oxidizer. The metal precursor and oxidizer are vaporized into a vacuum chamber. In some embodiments, the metal precursor and oxidizer are provided to the vacuum chamber together. In other embodiments, the metal precursor and oxidizer are provided to the vacuum chamber in alternating pulses. After a metal oxo-positive photoresist film having a desired thickness is formed, the process can be stopped. In one embodiment, after a metal oxo-positive photoresist film having a desired thickness is formed, an optional plasma treatment operation can be performed.

[0033] In one embodiment, a cycle including a pulse of a metal precursor vapor and a pulse of an oxidizer vapor can be repeated multiple times to provide a metal oxo-positive photoresist film having a desired thickness. In one embodiment, the order of the cycles can be switched. For example, the oxidizer vapor can be pulsed first, and the metal precursor vapor can be pulsed next. In one embodiment, the pulse duration of the metal precursor vapor can be substantially similar to the pulse duration of the oxidizer vapor. In other embodiments, the pulse duration of the metal precursor vapor can be different from the pulse duration of the oxidizer vapor. In one embodiment, the pulse duration can be between 0 seconds and 1 minute. In certain embodiments, the pulse duration can be between 1 second and 5 seconds. In one embodiment, each repetition of the cycle uses the same process gas. In other embodiments, the process gas can be changed between cycles. For example, a first cycle can utilize a first metal precursor vapor, and a second cycle can utilize a second metal precursor vapor. Subsequent cycles can continue alternating between the first metal precursor vapor and the second metal precursor vapor. In one embodiment, multiple oxidizer vapors can be alternated between cycles in a similar manner. In one embodiment, the optional plasma treatment of the operation may be performed after every cycle. That is, each cycle may include a pulse of metal precursor vapor, a pulse of oxidant vapor, and a plasma treatment. In an alternative embodiment, the optional plasma treatment of the operation may be performed after multiple cycles. In yet another embodiment, the optional plasma treatment operation may be performed after the completion of every cycle (i.e., as a post-treatment).

[0034] Providing a metal-oxo positive photoresist film using a dry deposition and oxidation treatment process, such as those described in the above embodiments, can achieve significant advantages over wet chemical methods. One such advantage is the elimination of wet by-products. Dry deposition processes eliminate liquid waste and simplify by-product removal. Furthermore, dry deposition processes can provide a more uniform positive photoresist layer. Uniformity in this sense can refer to the uniformity of thickness across the wafer and / or the uniformity of the distribution of the metal component of the metal-oxo film.

[0035] Furthermore, the use of dry deposition processes allows for fine tuning of the proportion of metal in the positive photoresist and the composition of the metal in the positive photoresist. The percentage of metal can be changed by increasing / decreasing the flow rate of the metal precursor into the vacuum chamber and / or by changing the pulse length of the metal precursor / oxidizer. The use of dry deposition processes also allows for the inclusion of multiple different metals in the metal-oxo film. For example, a single pulse of two different metal precursors can be used, or alternating pulses of two different metal precursors can be used.

[0036] Additionally, metal oxo-positive photoresists formed using dry deposition processes have been shown to be more resistant to thickness loss after exposure. Without being bound to a particular mechanism, the resistance to thickness loss is believed to be due, at least in part, to reduced carbon loss upon exposure.

[0037] In one embodiment, the vacuum chamber utilized in the dry deposition process is any suitable chamber capable of providing sub-atmospheric pressure. In one embodiment, the vacuum chamber may include temperature control features for controlling the temperature of the chamber walls and / or for controlling the temperature of the substrate. In one embodiment, the vacuum chamber may also include features for providing a plasma within the chamber. A more detailed description of a suitable vacuum chamber is provided below with respect to FIG. 3, which is a schematic diagram of a vacuum chamber configured to perform dry deposition of a metal oxo-positive photoresist, according to one embodiment of the present disclosure.

[0038] The vacuum chamber 300 includes a grounded chamber 305. A substrate 310 is loaded through an opening 315 and clamped to a temperature-controlled chuck 320. In one embodiment, the substrate 310 can be temperature-controlled during the dry deposition process. For example, the temperature of the substrate 310 can be between about -40°C and 200°C. In certain embodiments, the substrate 310 can be held at a temperature between room temperature and 150°C.

[0039] Process gases are supplied to the interior of the chamber 305 from gas sources 344 via respective mass flow controllers 349. In certain embodiments, a gas distribution plate 335 provides distribution of the process gases 344, such as metal precursors, oxidizers, and inert gases. The chamber 305 is evacuated via an exhaust pump 355. In one embodiment, one or more process gases are contained / stored in one or more ampoules. In one embodiment, the dry deposition process is a chemical vapor deposition condensation process, and the one or more ampoules are maintained at a temperature above the substrate temperature, for example, 25 degrees Celsius or higher, or higher than the substrate temperature.

[0040] When RF power is applied during processing of the substrate 310, a plasma is formed in the chamber processing region above the substrate 310. A bias power RF generator 325 is coupled to the temperature-controlled chuck 320. The bias power RF generator 325 provides bias power to energize the plasma as needed. The bias power RF generator 325 may have a low frequency, for example, between about 2 MHz and 60 MHz, and in certain embodiments, is in the 13.56 MHz band. In certain embodiments, the vacuum chamber 300 includes a third bias power RF generator 326, with a frequency in the 2 MHz band, connected to the same RF match 327 as the bias power RF generator 325. A source power RF generator 330 is coupled to a plasma generating element (e.g., a gas distribution time plate 335) via a match (not shown) to provide source power to energize the plasma. The source RF generator 330 may have a frequency, for example, between 100 and 180 MHz, and in certain embodiments, is in the 162 MHz band. As substrate diameters have progressed over time to 150 mm, 200 mm, 300 mm, etc., it is common in the art to normalize the source and bias power of plasma etching systems to the substrate area. Vacuum chamber 300 is controlled by controller 370. Controller 370 may include a CPU 372, a memory 373, and an I / O interface 374. CPU 372 may perform processing operations within vacuum chamber 300 according to instructions stored in memory 373. For example, one or more processes, such as processes 120 and 440 described above, may be performed within the vacuum chamber by controller 370.

[0041] In another aspect, embodiments disclosed herein include processing tools that include architectures particularly suited to optimizing dry deposition. For example, the processing tool may include a temperature-controlled pedestal for supporting the wafer. In some embodiments, the temperature of the pedestal may be maintained between about −40° C. and about 200° C. Additionally, an edge purge flow and shadow ring may be provided around the column on which the substrate is supported. The edge purge flow and shadow ring prevent positive photoresist from depositing along the edge or backside of the wafer. In one embodiment, the pedestal may provide any desired chuck configuration, including, but not limited to, a vacuum chuck, a monopolar chuck, or a bipolar chuck, depending on the operating region of the processing tool.

[0042] In some embodiments, the processing tool may be suitable for plasma-free deposition processes. Alternatively, the processing tool may include a plasma source that enables plasma-enhanced processing. Furthermore, while the embodiments disclosed herein are particularly suitable for depositing metal-oxo positive photoresists for EUV patterning, it should be understood that the embodiments are not limited to such configurations. For example, the processing tools described herein may be suitable for depositing any positive photoresist material for any type of lithography using dry deposition processes.

[0043] Referring now to FIG. 4, a cross-sectional view of a processing tool 400 is shown in accordance with one embodiment. In one embodiment, the processing tool 400 can include a chamber 405. The chamber 405 can be any suitable chamber capable of supporting sub-atmospheric pressure (e.g., vacuum pressure). In one embodiment, an exhaust system (not shown) including a vacuum pump can be coupled to the chamber 405 to provide the sub-atmospheric pressure. In one embodiment, a lid can seal the chamber 405. For example, the lid can include a showerhead assembly 440, etc. The showerhead assembly 440 can include fluid paths that allow process gases and / or inert gases to flow into the chamber 405. In some embodiments where the processing tool 400 is suitable for plasma-enhanced operation, the showerhead assembly 440 can be electrically coupled to an RF source and a matching circuit 450. In yet another embodiment, the tool 400 can be configured with an RF bottom-fed architecture. That is, the pedestal 430 is connected to an RF power source and the showerhead assembly 440 is grounded. In such an embodiment, a filtering circuit can still be connected to the pedestal. In one embodiment, the precursor gas is stored in an ampoule 499 .

[0044] In one embodiment, a movable column is provided within the chamber 405 to support the wafer 401. In one embodiment, the wafer 401 may be any substrate on which a positive photoresist material is deposited. For example, the wafer 401 may be a 300 mm wafer or a 450 mm wafer, although other wafer diameters may be used. Additionally, in some embodiments, the wafer 401 may be replaced with a substrate having a non-circular shape. The movable column may include pillars 414 extending outside the chamber 405. The pillars 414 may have ports for providing electrical and fluid paths from outside the chamber 405 to various components of the column.

[0045] In one embodiment, the column can include a base plate 410. The base plate 410 can be grounded. As described in more detail below, the base plate 410 can include fluid channels that allow for the flow of inert gas to provide an edge purge flow.

[0046] In one embodiment, an insulating layer 415 is disposed on the base plate 410. The insulating layer 415 may be any suitable dielectric material. For example, the insulating layer 415 may be a ceramic plate, etc. In one embodiment, a pedestal 430 is disposed on the insulating layer 415. The pedestal 430 may comprise a single material, or the pedestal 430 may be formed from different materials. In one embodiment, the pedestal 430 may utilize any suitable chuck system to secure the wafer 401. For example, the pedestal 430 may be a vacuum chuck or a monopolar chuck. In embodiments where a plasma is not generated in the chamber 405, the pedestal 430 may utilize a bipolar chuck structure.

[0047] The pedestal 430 may include a plurality of cooling channels 431. The cooling channels 431 may be connected to fluid inputs and outputs (not shown) that pass through the pillars 414. In one embodiment, the cooling channels 431 allow for control of the temperature of the wafer 401 during operation of the processing tool 400. For example, the cooling channels 431 may control the temperature of the wafer 401 between about −40° C. and about 200° C. In one embodiment, the pedestal 430 is connected to ground through a filtering circuit 445, which allows for DC and / or RF biasing of the pedestal relative to ground.

[0048] In one embodiment, an edge ring 420 surrounds the insulating layer 415 and the pedestal 430. The edge ring 420 may be a dielectric material, such as ceramic. In one embodiment, the edge ring 420 is supported by the base plate 410. The edge ring 420 may support a shadow ring 435. The shadow ring 435 has an inner diameter that is smaller than the diameter of the wafer 401. Thus, the shadow ring 435 prevents the positive photoresist from depositing on a portion of the outer edge of the wafer 401. A gap is provided between the shadow ring 435 and the wafer 401. The gap prevents the shadow ring 435 from contacting the wafer 401 and provides an outlet for the edge purge flow, which will be described in more detail below. In one embodiment, a dual-channel showerhead can be used in a positive photoresist manufacturing process.

[0049] Although the shadow ring 435 provides some protection to the top surface and edge of the wafer 401, process gases can flow / diffuse downward along the path between the edge ring 420 and the wafer 401. Therefore, embodiments disclosed herein can include a fluid path between the edge ring 420 and the pedestal 430 to enable edge purge flow. Providing an inert gas in the fluid path increases the local pressure in the fluid path, preventing process gases from reaching the edge of the wafer 401. Therefore, deposition of positive photoresist along the edge of the wafer 401 is prevented.

[0050] 5, an enlarged cross-sectional view of a portion of a column 560 in a processing tool is shown, according to one embodiment. Only the left end of the column 560 is shown in FIG. 5. However, it should be understood that the right end of the column 560 can substantially mirror the left end.

[0051] In one embodiment, the column 560 may include a base plate 510. An insulating layer 515 may be disposed on the base plate 510. In one embodiment, the pedestal 530 may include a first portion 530A and a second portion 530B. The cooling channel 531 may be disposed in the second portion 530B. The first portion 530A may include a mechanism for chucking the wafer 501.

[0052] In one embodiment, the edge ring 520 surrounds the base plate 510, the insulating layer 515, the pedestal 530, and the wafer 501. In one embodiment, the edge ring 520 is spaced apart from other components of the column 550 to provide a fluid pathway 512 from the base plate 510 to the top surface of the column 560. For example, the fluid pathway 512 may exit the column between the wafer 501 and the shadow ring 535. In certain embodiments, the inner surface of the fluid pathway 512 includes the edge of the insulating layer 515, the edge of the pedestal 530 (i.e., the first portion 530A and the second portion 530B), and the edge of the wafer 501. In one embodiment, the outer surface of the fluid pathway 512 includes the inner edge of the edge ring 520. In one embodiment, the fluid pathway 512 may continue onto the top surface of a portion of the pedestal 530 as it proceeds to the edge of the wafer 501. Thus, when an inert gas (eg, helium, argon, etc.) flows through fluid path 512 , process gases are prevented from flowing / diffusing down the sides of wafer 501 .

[0053] In one embodiment, the width W of the fluid path 512 is minimized to prevent plasma impingement along the fluid path 512. For example, the width W of the fluid path 512 may be about 1 mm or less. In one embodiment, a seal 517 prevents the fluid path 512 from exiting the bottom of the column 560. The seal 517 may be disposed between the edge ring 520 and the base plate 510. The seal 517 may be a flexible material, such as a gasket material. In a particular embodiment, the seal 517 comprises silicone.

[0054] In one embodiment, a channel 511 is disposed within the base plate 510. The channel 511 routes inert gas from the center of the column 560 to the inner edge of the edge ring 520. It should be understood that only a portion of the channel 511 is shown in Figure 5. A more comprehensive view of the channel 511 is provided below with respect to Figure 7B.

[0055] In one embodiment, the edge ring 520 and the shadow ring 535 may have features suitable for aligning the shadow ring 535 with respect to the wafer 501. For example, a notch 521 on the top surface of the edge ring 520 may contact a protrusion 536 on the bottom surface of the shadow ring 535. The notch 521 and protrusion 536 may have tapered surfaces that allow for coarse alignment of the two components sufficiently to provide more precise alignment when the edge ring 520 contacts the shadow ring 535. In additional embodiments, alignment features (not shown) may also be provided between the pedestal 530 and the edge ring 520. The alignment features between the pedestal 530 and the edge ring 520 may include tapered notch and protrusion structures similar to the alignment features between the edge ring 520 and the shadow ring 535.

[0056] 6A and 6B, a pair of cross-sectional views are shown illustrating a portion of a processing tool with a pedestal in different positions (in the Z direction), according to one embodiment. In FIG. 6A, the pedestal is in a lowered position within the chamber. The pedestal position in FIG. 6A is where a wafer is inserted into or removed from the chamber through a slit valve. In FIG. 6B, the pedestal is in a raised position within the chamber. The pedestal position in FIG. 6B is where a wafer is processed.

[0057] Referring now to FIG. 6A, a cross-sectional view of a movable column 660 in a first position is shown, according to one embodiment. As shown in FIG. 6A, the column includes a base plate 610, an insulating layer 615, a pedestal 630 (i.e., a first portion 630A and a second portion 630B), and an edge ring 620. Such components may be substantially similar to the similarly named components described above. For example, cooling channels 631 may be provided in the second portion 630B of the pedestal 630, channels 611 may be disposed in the base plate 610, and a seal 617 may be provided between the edge ring 620 and the base plate 610.

[0058] As shown in Figure 6A, wafer 601 is placed on top of pedestal 630. Wafer 601 can be inserted into the chamber through a slit valve (not shown). Additionally, shadow ring 635 is shown in a raised position above edge ring 620. Because the inner diameter of shadow ring 635 is smaller than the diameter of wafer 601, wafer 601 must be placed on the pedestal before shadow ring 635 contacts edge ring 620.

[0059] In one embodiment, the shadow ring 635 is supported by a chamber liner 670. The chamber liner 670 can surround the outer periphery of the column 660. In one embodiment, a holder 671 is disposed on the top surface of the chamber liner 670. The holder 671 is configured to hold the shadow ring 635 in an elevated position above the edge ring 620 when the column 660 is in the first position. In one embodiment, the shadow ring 635 includes a protrusion 636 for aligning with a notch 621 in the edge ring 620.

[0060] 6B , a cross-sectional view of the column 660 after the shadow ring 635 has been engaged is shown, according to one embodiment. As shown, the column 660 is displaced vertically (i.e., in the Z direction) until the shadow ring 635 engages the edge ring 620. Further vertical displacement of the column 660 causes the shadow ring 635 to lift from the holder 671 on the chamber liner 670. In one embodiment, the shadow ring 635 is properly aligned as a result of alignment features (i.e., the notch 621 and the protrusion 636) on the shadow ring 635 and the edge ring 620. In additional embodiments, an alignment mechanism (not shown) can also be provided between the pedestal 630 and the edge ring 620. The alignment features between the pedestal 630 and the edge ring 620 can include a tapered notch and protrusion structure similar to the alignment features between the edge ring 620 and the shadow ring 635.

[0061] While in the second position, the wafer 601 can be processed. In particular, the processing can include deposition of a positive photoresist material on the top surface of the wafer 601. For example, the process can be a dry deposition and oxidation treatment process, with or without plasma assistance. In a particular embodiment, the positive photoresist is a metal-oxo positive photoresist suitable for EUV patterning. However, it should be understood that the positive photoresist can be any type of positive photoresist, and the patterning can include any lithography method. During deposition of the positive photoresist on the wafer 601, an inert gas can be flowed along fluid channels between the inner surface of the edge ring 610 and the insulating layer 615, the pedestal 630, and the outer surface of the wafer 601. Thus, deposition of the positive photoresist along the edge or backside of the wafer 601 is substantially eliminated. In one embodiment, the wafer temperature 601 can be maintained between approximately −40° C. and approximately 200° C. by cooling channels 631 in the second portion of the pedestal 630B.

[0062] 7A, a cross-sectional view of a processing tool 700 according to an additional embodiment is shown. As shown in FIG. 7A, the column includes a base plate 710. The base plate 710 may be supported by pillars 714 that extend outside the chamber. That is, in some embodiments, the base plate 710 and pillars 714 may be separate components rather than a single monolithic part as shown in FIG. 4. The pillars 714 may have central channels for routing electrical connections and fluids (e.g., cooling fluid and inert gas for purge flow).

[0063] In one embodiment, an insulating layer 715 is disposed on the base plate 710, and a pedestal 730 (i.e., a first portion 730A and a second portion 730B) is disposed on the insulating layer 715. In one embodiment, a coolant channel 731 is provided in the second portion 730B of the pedestal 730. The wafer 701 is disposed on the pedestal 730.

[0064] In one embodiment, an edge ring 720 is provided around the base plate 710, insulating layer 715, pedestal 730, and wafer 701. The edge ring 720 may be coupled to the base plate 713 by a fastening mechanism 713, such as bolts, pins, screws, etc. In one embodiment, a seal 717 prevents purge gas from exiting the column from the bottom between the gap between the base plate 710 and the edge ring 720.

[0065] In the illustrated embodiment, the pedestal 730 is in a first position. Thus, the shadow ring 735 is supported by the holder 771 and the chamber liner 770. As the pedestal 730 is displaced vertically, the edge ring 720 engages the shadow ring 735 and lifts the shadow ring 735 off the holder 771.

[0066] Referring now to FIG. 7B , a cross-sectional view of a chamber 700 according to an additional embodiment is shown. In the view of FIG. 7B , the insulating layer 715 and pedestal 730 have been omitted to more clearly illustrate the structure of the base plate 710. As shown, the base plate 710 may include a plurality of channels 711 that provide a fluid path from the center of the base plate 710 to the edge of the base plate 710. In the illustrated embodiment, a plurality of first channels connect the center of the base plate 710 to a first ring channel, and a plurality of second channels connect the first ring channel to the outer edge of the base plate 710. In one embodiment, the first and second channels are offset from one another. While a particular configuration of channels 711 is shown in FIG. 7B , it should be understood that any channel configuration can be used to route inert gas from the center of the base plate 710 to the edge of the base plate 710.

[0067] FIG. 8 illustrates a diagrammatic representation of a machine in the exemplary form of a computer system 800 within which a set of instructions for causing the machine to perform any one or more of the methodologies described herein may be executed. In alternative embodiments, the machine may be connected (e.g., networked) to other machines in a local area network (LAN), an intranet, an extranet, or the Internet. The machine may operate as a server or a client machine in a client / server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The machine may be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile phone, a web appliance, a server, a network router, a switch, or a bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be performed by the machine. Furthermore, while a single machine is illustrated, the term “machine” should also be interpreted to include any collection of machines (e.g., computers) that, individually or jointly, execute a set (or sets) of instructions to perform any one or more of the methodologies described herein.

[0068] The exemplary computer system 800 includes a processor 802, a main memory 804 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM), etc.), a static memory 806 (e.g., flash memory, static random access memory (SRAM), MRAM, etc.), and a secondary storage device 818 (e.g., a data storage device), which communicate with each other via a bus 830.

[0069] Processor 802 represents one or more general-purpose processing devices, such as a microprocessor or central processing unit. More specifically, processor 802 may be a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a processor implementing other instruction sets, or a processor implementing a combination of instruction sets. Processor 802 may also be one or more special-purpose processing devices, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a digital signal processor (DSP), a network processor, or the like. Processor 802 is configured to execute processing logic 826 to perform the operations described herein.

[0070] Computer system 800 may further include a network interface device 808. Computer system 800 may include a video display device 810 (e.g., a liquid crystal display (LCD), a light emitting diode display (LED), or a cathode ray tube (CRT)), an alphanumeric input device 812 (e.g., a keyboard), a cursor control device 814 (e.g., a mouse), and a signal generating device 816 (e.g., a speaker).

[0071] Secondary memory 818 may include a machine-accessible storage medium (or more specifically, a computer-readable storage medium) 832 on which is stored one or more sets of instructions (e.g., software 822) that embody any one or more of the methodologies or functions described herein. The software 822 may reside, completely or at least partially, within main memory 804 and / or processor 802, which also constitute machine-readable storage media, while being executed by computer system 800. This software 822 may also be transmitted or received over network 820 via network interface device 808.

[0072] Although machine-accessible storage medium 832 is shown as a single medium in the exemplary embodiment, the term "machine-readable storage medium" should be interpreted to include a single medium or multiple media (e.g., centralized or distributed databases and / or associated caches and servers) that store one or more sets of instructions. The term "machine-readable storage medium" should also be interpreted to include any medium capable of storing or encoding a set of instructions that are executed by a machine, causing the machine to perform any one or more of the methods of the present invention. Accordingly, the term "machine-readable storage medium" should be interpreted to include, but is not limited to, solid-state memory, optical media, and magnetic media.

[0073] According to one embodiment of the present disclosure, a machine-accessible storage medium has stored thereon instructions for causing a data processing system to perform a method for forming a positive photoresist layer on a substrate in a vacuum chamber. The method includes providing a metal precursor vapor in the vacuum chamber. The method also includes providing an oxidizer vapor in the vacuum chamber. A reaction between the metal precursor vapor and the oxidizer vapor forms a positive photoresist layer on the surface of the substrate.

[0074] Thus, a method for forming a positive photoresist using a dry process has been disclosed.

Claims

1. 1. A method for forming a photoresist layer on a substrate in a vacuum chamber, comprising: providing a metal precursor vapor into the vacuum chamber; providing an oxidant vapor within the vacuum chamber, wherein a reaction between the metal precursor vapor and the oxidant vapor results in chemical vapor deposition (CVD) of a positive photoresist layer on the surface of the substrate, the positive photoresist layer being a metal-oxo-containing material; performing a post-annealing treatment of the metal-oxo-containing material in an oxygen-containing environment; 1. A method for forming a photoresist layer on a substrate in a vacuum chamber, comprising:

2. The post-annealing treatment is carried out using ozone (O ３ 10. The method of claim 1, wherein the method is performed using

3. The method of claim 2, wherein the post-annealing treatment is carried out at a temperature in the range of 25 to 250 degrees Celsius.

4. The method of claim 3 , wherein the post-annealing treatment is carried out at a pressure less than 200 Torr.

5. The method of claim 1 , wherein the chemical vapor deposition (CVD) is a thermal CVD process.

6. The metal precursor vapor (PhSn(NMe ２ ) ３ 6. The method of claim 5, wherein the polyisocyanate is formed from

7. The method of claim 1 , wherein the chemical vapor deposition (CVD) is a plasma-enhanced CVD process.

8. The metal precursor vapor (PhSn(NMe ２ ) ３ 8. The method of claim 7, wherein the polyisocyanate is formed from

9. The metal precursor vapor is Sn(nBu) ４ 8. The method of claim 7, wherein the compound is formed from

10. The method of claim 1 , wherein the chemical vapor deposition (CVD) is not a condensation process.

11. The method of claim 1 , wherein the chemical vapor deposition (CVD) is a condensation process.

12. 12. The method of claim 11 , wherein the metal precursor vapor is provided into the vacuum chamber from an ampoule maintained at a first temperature, and the substrate is maintained at a second temperature lower than the first temperature during formation of the positive photoresist layer on the surface of the substrate.

13. 1. A method for forming a photoresist layer on a substrate in a vacuum chamber, comprising: providing a metal precursor vapor into the vacuum chamber; providing an oxidant vapor within the vacuum chamber, wherein a reaction between the metal precursor vapor and the oxidant vapor results in atomic layer deposition (ALD) of a positive tone photoresist layer on the surface of the substrate, the positive tone photoresist layer being a metal-oxo-containing material; performing a post-annealing treatment of the metal-oxo-containing material in an oxygen-containing environment; 1. A method for forming a photoresist layer on a substrate in a vacuum chamber, comprising:

14. 14. The method of claim 13, wherein the atomic layer deposition (ALD) is a thermal ALD process.

15. 14. The method of claim 13, wherein the atomic layer deposition (ALD) is a plasma-enhanced ALD process.

16. The metal precursor vapor (PhSn(NMe ２ ) ３ 14. The method of claim 13, wherein the polymer is formed from

17. The metal precursor vapor is Sn(nBu) ４ 14. The method of claim 13, wherein the compound is formed from

18. 1. A method for forming a photoresist layer on a substrate in a vacuum chamber, comprising: providing a metal precursor vapor into the vacuum chamber; providing an oxidant vapor within the vacuum chamber, wherein a reaction between the metal precursor vapor and the oxidant vapor results in the deposition of a positive photoresist layer on the surface of the substrate, the positive photoresist layer being a metal-oxo-containing material; Ozone (O ３ ) annealing the positive photoresist layer in an oxygen-containing environment based on a source gas; exposing a portion of the positive photoresist layer to an extreme ultraviolet (EUV) energy source; developing the positive photoresist layer using a basic developer; 1. A method for forming a photoresist layer on a substrate in a vacuum chamber, comprising:

19. The metal precursor vapor (PhSn(NMe ２ ) ３ 20. The method of claim 18, wherein the polymer is formed from

20. The metal precursor vapor is Sn(nBu) ４ 20. The method of claim 18, wherein the compound is formed from

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