Vapor-phase thermal etching method for metal oxo photoresists.

Abstract

To provide a method for developing metal oxo photoresist.SOLUTION: The method includes providing a substrate with metal oxo photoresist including exposed regions and unexposed regions into a vacuum chamber. In one embodiment, the unexposed regions have a higher carbon concentration than the exposed regions. The method may further include vaporizing a halogenating agent in the vacuum chamber, where the halogenating agent reacts with either the unexposed regions or the exposed regions to produce a volatile byproduct. The method may further include purging the vacuum chamber.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Nonprovisional Application No. 17 / 348,589, filed June 15, 2021, which claims the benefit of U.S. Provisional Application No. 63 / 047,157, filed July 1, 2020, the entire contents of which are incorporated herein by reference.

[0002] TECHNICAL FIELD Embodiments of the present disclosure relate to the field of semiconductor processing, and in particular to a method for developing metal-oxo photoresists using a gas phase process. [Background technology]

[0003] 2. Description of Related Art Lithography has been used in the semiconductor industry for decades to create 2D and 3D patterns in microelectronic devices. The lithography process involves spin-on deposition of a film (photoresist), irradiating the film with an energy source with a selected pattern (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 performed to drive off any residual solvent.

[0004] The photoresist should be a radiation-sensitive material, and when irradiated, a chemical transformation occurs in the exposed parts of the film, which allows the solubility to change 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 now developed, and the pattern can be transferred to the underlying thin film or substrate by etching. After the pattern is transferred, the remaining photoresist is removed. This process can be repeated many times to obtain 2D and 3D structures used in microelectronic devices.

[0005] Several properties are important in the lithography process. Such properties include sensitivity, resolution, low line edge roughness (LER), etch resistance, and ability to form thin layers. The higher the sensitivity, the less energy is required to change the solubility of the deposited film. This allows for improved efficiency in the lithography process. Resolution and LER determine how narrow features can be achieved by the lithography process. Pattern transfer to form deep structures requires materials with high etch resistance. Materials with high etch resistance also allow for thinner films. The thinner the film, the more efficient the lithography process. Summary of the Invention

[0006] Embodiments disclosed herein include a method of developing a metal-oxo photoresist. In one embodiment, the method includes providing a substrate having a metal-oxo photoresist in a vacuum chamber, the metal-oxo photoresist including exposed and unexposed regions. In one embodiment, the unexposed regions have a higher carbon concentration than the exposed regions. The method may further include vaporizing a halogenating agent in the vacuum chamber, where the halogenating agent reacts with either the unexposed or exposed regions to generate volatile by-products. In one embodiment, the method may further include purging the vacuum chamber.

[0007] The method of developing a metal-oxo photoresist may further include providing a substrate having the metal-oxo photoresist, including exposed and unexposed regions, in a vacuum chamber. In one embodiment, the unexposed regions have a higher carbon concentration than the exposed regions. The method may further include vaporizing a halogenating agent in the vacuum chamber, where the halogenating agent reacts with either the unexposed regions or the exposed regions to produce a non-volatile product. In one embodiment, the method may further include vaporizing a ligand in the vacuum chamber, where the ligand reacts with the non-volatile product to produce a volatile by-product. In one embodiment, the method may further include purging the vacuum chamber.

[0008] The method of developing a metal-oxo photoresist may further include providing a substrate having the metal-oxo photoresist, including exposed and unexposed regions, in a vacuum chamber. In one embodiment, the unexposed regions have a higher carbon concentration than the exposed regions. The method may further include vaporizing an organic acid in the vacuum chamber, where the organic acid reacts with either the unexposed regions or the exposed regions to generate volatile by-products. In one embodiment, the method may further include purging the vacuum chamber. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a flow diagram illustrating a process for developing a metal-oxo photoresist using a gas phase process with a halogenating agent according to one embodiment of the present disclosure. [Figure 2A] 2A-2C are cross-sectional views of a substrate and photoresist illustrating a step in the flow diagram of FIG. 1 according to one embodiment of the present disclosure. [Figure 2B] 2A-2C are cross-sectional views of a substrate and photoresist illustrating a step in the flow diagram of FIG. 1 according to one embodiment of the present disclosure. [Figure 2C] 2A-2C are cross-sectional views of a substrate and photoresist illustrating a step in the flow diagram of FIG. 1 according to one embodiment of the present disclosure. [Diagram 3] FIG. 1 is a flow diagram illustrating a process for developing a metal-oxo photoresist using a gas phase process with a halogenating agent and a protonated ligand according to one embodiment of the present disclosure. [Figure 4A] 4A-4C are cross-sectional views of a substrate and photoresist illustrating a step in the flow diagram of FIG. 3 according to one embodiment of the present disclosure. [Figure 4B] 4A-4C are cross-sectional views of a substrate and photoresist illustrating a step in the flow diagram of FIG. 3 according to one embodiment of the present disclosure. [Figure 4C] 4A-4C are cross-sectional views of a substrate and photoresist illustrating a step in the flow diagram of FIG. 3 according to one embodiment of the present disclosure. [Diagram 5]FIG. 2 is a flow diagram illustrating a process for developing a metal-oxo photoresist using a gas phase process with an organic acid according to one embodiment of the present disclosure. [Figure 6A] 6A-6C are cross-sectional views of a substrate and photoresist illustrating a step in the flow diagram of FIG. 5 according to one embodiment of the present disclosure. [Figure 6B] 6A-6C are cross-sectional views of a substrate and photoresist illustrating a step in the flow diagram of FIG. 5 according to one embodiment of the present disclosure. [Figure 7] 6 is a cross-sectional view of a processing tool that may be used to implement portions of the process of FIG. 1, FIG. 3, or FIG. 5 according to one embodiment of the present disclosure. [Figure 8] FIG. 1 illustrates a block diagram of an exemplary computer system according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] This document describes a method for developing metal-oxo photoresist using a gas phase process. In the following description, numerous specific details for developing photoresist (such as thermal gas phase processes and material regimes) are set forth in order to provide a comprehensive understanding of the embodiments of the present disclosure. It will be apparent to one of ordinary skill in the art that the embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known aspects (such as the fabrication of integrated circuits) have not been described in detail in order to not unnecessarily obscure the embodiments of the present disclosure. Furthermore, it should be understood that the various embodiments depicted in the figures are illustrative representations and are not necessarily drawn to scale.

[0011] To further aid in understanding, photoresist systems used in extreme ultraviolet (EUV) lithography suffer from inefficiencies. That is, existing photoresist material systems for EUV lithography require high doses to provide the solubility switch necessary to enable development of the photoresist material. Organic-inorganic hybrid materials (e.g., metal-oxo material systems) have been proposed as material systems for EUV lithography due to their high sensitivity to EUV radiation. Such material systems typically include metals (e.g., Sn, Hf, Zr, etc.), oxygen, and carbon. Metal-oxo-based organic-inorganic hybrid materials have also been found to provide low LER and high resolution, which are necessary properties for forming narrow features.

[0012] In metal-oxo photoresist systems, carbon is removed by exposure to EUV radiation. The difference in carbon percentage between exposed and unexposed areas is used as a solubility switch during development. Specifically, in negative tone development, unexposed areas with high carbon content are preferentially etched by the developer.

[0013] Metal-oxo photoresist systems are currently developed using wet chemistry; that is, after exposure, the unexposed areas of the photoresist are developed by an organic solvent / base solution used in a spin-dry process. A post-bake annealing step may also be included. However, when addressing high aspect ratio features, wet methods can be challenging due to the risk of pattern collapse (especially for line and pillar structures). In addition, wet processes may not remove all the material that should be removed, and may trap film material / by-products / solvents etc. in small features.

[0014] Thus, embodiments of the present disclosure provide a gas-phase thermal etching process for developing metal-oxo photoresists, which in particular: 1) eliminates the production of wet by-products, 2) reduces defects and impurities, 3) reduces waste streams due to the destruction of dry chemicals in the abatement system, 4) improves LER, and 5) causes less damage from dry thermal etching compared to plasma damage in reactive ion etching (RIE). For example, at pitches less than 30 nm (e.g., line CDs less than 14 nm) and photoresist thicknesses less than 15 nm, the plasma can damage the photoresist mask, which can result in LER / LWR defects or even destruction of the line pattern when the pattern is transferred to the underlying layer.

[0015] The embodiments disclosed herein provide various gas-phase thermal etching processes that are performed after the metal-oxo photoresist is partially exposed to a suitable electromagnetic radiation source (e.g., an EUV source). In a first embodiment, the gas-phase thermal etching process includes vaporizing a halogenating agent in a vacuum chamber. The halogenating agent may react with either the unexposed or exposed regions of the photoresist to produce volatile by-products, which are removed from the vacuum chamber. In a second embodiment, the gas-phase thermal etching process includes vaporizing a halogenating agent in a vacuum chamber. The halogenating agent may react with either the unexposed or exposed regions of the photoresist to produce non-volatile products. A ligand may then be vaporized in the chamber. The ligand may react with the non-volatile products to result in volatile by-products, which are removed from the vacuum chamber. In a third embodiment, the gas-phase thermal etching process includes vaporizing an organic acid in a vacuum chamber. The organic acid may react with either the unexposed or exposed regions of the photoresist to produce volatile by-products, which are removed from the vacuum chamber.

[0016] 1, a flow diagram illustrating a process 120 for developing a metal-oxo photoresist on a substrate surface is provided, according to one embodiment of the present disclosure. Figures 2A-2C are cross-sectional views of a substrate 261 and a metal-oxo photoresist 262 after various steps in the process 120.

[0017] In one embodiment, the process 120 may begin at step 121 with providing a substrate having a metal-oxo photoresist. FIG. 2A is a cross-sectional view of the substrate 261 with a metal-oxo photoresist 262 disposed over a surface of the substrate 261. In one embodiment, the substrate 261 may include any substrate material or materials characteristic of a semiconductor manufacturing environment. For example, the substrate 261 may include a semiconductor material. The substrate 261 may include a semiconductor device or a portion of a semiconductor device. Examples of such semiconductor devices include, but are not limited to, memory devices or complementary metal oxide semiconductor (CMOS) transistors fabricated in a silicon substrate and encapsulated in a dielectric layer. The substrate 261 may further include a plurality of metal interconnects formed in the surrounding dielectric layer above the devices or transistors and may be used to electrically couple the devices or transistors to form an integrated circuit. In one embodiment, the substrate 261 may be a wafer.

[0018] In one embodiment, the metal-oxo photoresist 262 (also referred to simply as "photoresist 262") can be any metal-oxo material system. Such material systems typically include a metal (e.g., Sn, Hf, Zr, etc.), oxygen, and carbon. In one particular embodiment, the photoresist 262 includes SnOC.

[0019] The photoresist 262 may be disposed on the surface of the substrate 261 using any suitable deposition process. In one embodiment, the photoresist is disposed on the surface of the substrate 261 by wet chemistry using a spin-on process. In an alternative embodiment, the photoresist is disposed on the surface of the substrate 261 using a gas phase process (i.e., a dry process). In a gas phase process, a metal precursor and an oxidant may be vaporized into a vacuum chamber. The metal precursor and the oxidant then react to deposit a metal-oxo photoresist 262 on the surface of the substrate 261. Such dry processes may be characterized as a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, a plasma-enhanced CVD (PE-CVD) process, or a plasma-enhanced ALD (PE-ALD) process.

[0020] In one embodiment, the process 120 may continue with step 122, which includes partially exposing the metal-oxo photoresist to create exposed and unexposed regions. FIG. 2B is a cross-sectional view illustrating the exposure process. As shown, electromagnetic radiation 264 passes through a mask 263 to expose exposed regions 262E. Unexposed regions 262U are shielded from the electromagnetic radiation by the mask 263. In one embodiment, the electromagnetic radiation is EUV radiation. If EUV radiation is used, the EUV radiation 264 may reflect off the mask rather than passing through it. Although EUV radiation is specifically disclosed herein, it should be appreciated that any suitable wavelength of electromagnetic radiation capable of triggering a solubility switch in the metal-oxo photoresist 262 may be used. For example, in some embodiments, DUV radiation may be used.

[0021] In one embodiment, the solubility switch is effected by carbon loss, specifically, exposure to electromagnetic radiation removes carbon from exposed regions 262E, and the increased carbon content of unexposed regions 262U makes them more susceptible to etching in a subsequent gas phase development process.

[0022] In one embodiment, the process 120 may continue to step 123, which includes placing the substrate in a vacuum chamber. In one embodiment, the vacuum chamber may be any chamber suitable for providing sub-atmospheric pressure conditions. The vacuum chamber may also include heating / cooling capabilities to provide thermal control of gas phase processes. For example, the pedestal on which the substrate 261 rests may be an actively heated and / or cooled pedestal. Additionally, in some embodiments, the walls of the vacuum chamber may be actively heated and / or cooled.

[0023] In particular, it should be appreciated that in the embodiments disclosed herein, a plasma source is not required to implement gas phase etching of the metal-oxo photoresist. Thus, the construction of the vacuum chamber may be simplified as compared to processes involving plasma-based development of the metal-oxo photoresist. A more detailed description of a suitable vacuum chamber is provided below in connection with FIG. 7.

[0024] In one embodiment, the process 120 may continue with step 124, which includes vaporizing the halogenation agent in a vacuum chamber. In one embodiment, the halogenation agent reacts with the non-exposed regions 262U to produce volatile by-products. That is, the reaction between the halogenation agent and the non-exposed regions 262U removes the non-exposed regions 262U from the substrate 261, as shown in FIG. 2C. In other embodiments, the halogenation agent may react with the exposed regions 262E to produce volatile by-products. In one embodiment, the by-products of the reaction are volatile metal halides. Some metal halides have higher volatility than others. For example, SnCl4 has higher volatility than SnCl2, CoClL (where L is a ligand) has higher volatility than CoCl2, and MoOCl4 has higher volatility than MoCl5. Thus, the reaction may preferentially form by-products with higher volatility. In one embodiment, the by-product may have the formula MXx or MOyXx, where M is a metal or metalloid, X is a halide, x is 1-6, and y is 1-5.

[0025] In one embodiment, the halogenation agent is a metal halide of formula MXa or MXaLb, where M is a metal or metalloid (e.g., Mo, W, Ta, Nb, Sn, V, Ti, or Si), X is a halide (e.g., Cl or Br), L is a volatile ligand (e.g., an alkyl group, ethylenediamine, or Cp), a is 1 to 6, and b is 1 to 5. For example, the metal halide can include MoCl5, TaCl5, NbCl5, or WCl5.

[0026] In additional embodiments, the halogenating agent is a metal oxyhalide of formula MOaXb or MOaXbLc, where M is a metal or metalloid (e.g., Mo, W, Ta, Nb, Sn, V, Ti, or Si), X is a halide (e.g., Cl or Br), L is a volatile ligand (e.g., an alkyl group, ethylenediamine, or Cp), a is 1 to 5, b is 1 to 5, and c is 1 to 5. For example, the metal oxyhalide can include MoOCl4, MoO2Cl2, WOCl4, or WO2Cl2.

[0027] In yet another additional embodiment, the halogenating agent can be an organic halogenating agent. For example, the halogenating agent can be thionyl chloride (SOCl2), methanesulfonyl chloride (CH3SO2Cl), trichloromethanesulfonyl chloride (CCl3SO2Cl), 4-toluenesulfonyl chloride (tosyl chloride), oxalyl chloride (ClCOCOCl), tert-butyl hypochlorite ((CH3)3COCl), N-chlorophthalimide, 1,3-dichloro-5,5-dimethylhydantoin, trimethylsilyl chloride, HCl, Cl2, PCl5, These may include BCl3, HBr, Br2, CCl3Br, CBr4, 1,2-dibromo-1,1,2,2-tetrachloroethane (Cl2CBrCBrCl2), BBr3, PBr3, N-bromosuccinimide, N-bromoacetamide, 2-bromo-2-cyano-N,N-dimethylacetamide, 1,3-dibromo-5,5-dimethylhydantoin, 2,4,4,6-tetrabromo-2,5-cyclohexadienone, or trimethylsilyl bromide.

[0028] In yet another embodiment, the halogenating agent may include one or more of SOBr2 (thionyl bromide), SO2Cl2 (sulfuryl chloride), and SO2Br2 (sulfuryl bromide).

[0029] In one embodiment, the halogenating agent may be diluted with an inert gas. For example, an inert gas (such as Ar, N2, or He) may be used to dilute the halogenating agent. It has been found that the etch selectivity of the unexposed regions 262U of the photoresist relative to the exposed regions 262E of the photoresist typically increases with increasing pressure. In one embodiment, the pressure may be between about 1 Torr and about 100 Torr. In a particular embodiment, the pressure may be between about 3 Torr and about 10 Torr.

[0030] In one embodiment, in step 124, the substrate 261 may have a controlled temperature. For example, the temperature may vary between approximately 0° C. and approximately 500° C. In one particular embodiment, the temperature may vary between approximately 50° C. and approximately 200° C. It has been found that increasing the substrate temperature typically increases the etch selectivity of the unexposed regions of the photoresist 262U relative to the exposed regions of the photoresist 262E.

[0031] In one embodiment, process 120 may continue with step 125, which includes purging the vacuum chamber. Purging the vacuum chamber removes by-products from the reaction in step 124 from the vacuum chamber. In one embodiment, step 124 may be implemented as a soak followed by a single purge in step 125. In an alternative embodiment, steps 124 and 125 may define a cycle including a pulse of halogenating agent followed by a purge. In such an embodiment, multiple cycles may be repeated to remove unexposed regions 262U of the photoresist.

[0032] Referring now to FIG. 3, a flow diagram illustrating a process 330 for patterning a metal-oxo photoresist according to one embodiment of the present disclosure is shown. FIGS. 4A-4C are corresponding cross-sectional views illustrating various processing steps in the process 330. In one embodiment, the process 330 may be beneficial when the halogenating agent is not able to completely convert the unexposed areas of the photoresist into volatile by-products. In particular, the process 330 further includes vaporizing a protonated ligand in a vacuum chamber to convert the unexposed areas of the photoresist into volatile by-products.

[0033] In one embodiment, process 330 may begin at step 331 with providing a substrate having a metal-oxo photoresist. In one embodiment, the substrate and metal-oxo photoresist may be substantially similar to the substrate and metal-oxo photoresist described above in connection with step 121 of process 120.

[0034] In one embodiment, process 330 may continue with step 332, which includes partially exposing the metal oxo photoresist to create exposed and unexposed regions. In one embodiment, the exposure process of step 332 may be substantially similar to the exposure process of step 122 of process 120. Figure 4A presents a cross-sectional view of substrate 461, exposed region 462E of photoresist, and unexposed region 462U of photoresist.

[0035] In one embodiment, process 330 may continue with step 333, which includes placing the substrate in a vacuum chamber. The vacuum chamber used in process 330 may be substantially similar to the vacuum chamber used in process 120.

[0036] In one embodiment, the process 330 may continue with step 334, which includes vaporizing a halogenation agent in the vacuum chamber. In one embodiment, the halogenation agent may react with the unexposed regions 462U of the photoresist to provide a non-volatile product 462U′. That is, in some embodiments, the halogenation agent, by itself, may not be able to completely convert the unexposed regions 462U of the photoresist to a volatile product that can be removed from the vacuum chamber. In other embodiments, the halogenation agent may react with the exposed regions 462E to produce a non-volatile product. In one embodiment, the non-volatile product 462U′ may be a metal halide or metal oxyhalide of formula MXx or MOyXx, where M is a metal or metalloid, X is a halide, x is 1-6, and y is 1-5.

[0037] In one embodiment, the halogenation agent is a metal halide of formula MXa or MXaLb, where M is a metal or metalloid (e.g., Mo, W, Ta, Nb, Sn, V, Ti, or Si), X is a halide (e.g., Cl or Br), L is a volatile ligand (e.g., an alkyl group, ethylenediamine, or Cp), a is 1 to 6, and b is 1 to 5. For example, the metal halide can include MoCl5, TaCl5, NbCl5, or WCl5.

[0038] In additional embodiments, the halogenating agent is a metal oxyhalide of formula MOaXb or MOaXbLc, where M is a metal or metalloid (e.g., Mo, W, Ta, Nb, Sn, V, Ti, or Si), X is a halide (e.g., Cl or Br), L is a volatile ligand (e.g., an alkyl group, ethylenediamine, or Cp), a is 1 to 5, b is 1 to 5, and c is 1 to 5. For example, the metal oxyhalide can include MoOCl4, MoO2Cl2, WOCl4, or WO2Cl2.

[0039] In yet another additional embodiment, the halogenating agent can be an organic halogenating agent. For example, the halogenating agent can be thionyl chloride (SOCl2), methanesulfonyl chloride (CH3SO2Cl), trichloromethanesulfonyl chloride (CCl3SO2Cl), 4-toluenesulfonyl chloride (tosyl chloride), oxalyl chloride (ClCOCOCl), tert-butyl hypochlorite ((CH3)3COCl), N-chlorophthalimide, 1,3-dichloro-5,5-dimethylhydantoin, trimethylsilyl chloride, HCl, Cl2, PCl5, These may include BCl3, HBr, Br2, CCl3Br, CBr4, 1,2-dibromo-1,1,2,2-tetrachloroethane (Cl2CBrCBrCl2), BBr3, PBr3, N-bromosuccinimide, N-bromoacetamide, 2-bromo-2-cyano-N,N-dimethylacetamide, 1,3-dibromo-5,5-dimethylhydantoin, 2,4,4,6-tetrabromo-2,5-cyclohexadienone, or trimethylsilyl bromide.

[0040] In one embodiment, the halogenating agent may be diluted with an inert gas. For example, an inert gas (such as Ar, N2, or He) may be used to dilute the halogenating agent. In one embodiment, the pressure may be between about 1 Torr and about 100 Torr. In a particular embodiment, the pressure may be between about 5 Torr and about 10 Torr. In one embodiment, in step 334, the substrate 461 may have a controlled temperature. For example, the temperature may vary between about 0° C. and about 500° C. In a particular embodiment, the temperature may vary between about 50° C. and about 150° C.

[0041] In one embodiment, the process 330 may continue to step 335, which includes purging the vacuum chamber with an inert purge. In one embodiment, the purging process removes by-products and any unreacted halogenating agent.

[0042] In one embodiment, the process 330 may continue to step 336, which includes vaporizing the ligand in a vacuum chamber. In one embodiment, the ligand reacts with the non-volatile product 462U′ to generate a volatile by-product. That is, the reaction between the vaporized ligand and the non-volatile product 462U′ removes the non-exposed regions from the substrate 461, as shown in FIG. 4C. If a non-volatile product is generated from the exposed region 462E, the exposed region may be removed from the substrate 461. In one embodiment, the ligand is a protonated ligand (such as an amine). In one embodiment, the ligand may be diluted with an inert gas (such as Ar, N2, or He). In one embodiment, the volatile by-products may have the formula MXxLy or MOxXyLz, where M is a metal or metalloid (e.g., Mo, W, Ta, Nb, Sn, V, Ti, or Si), X is a halide (e.g., Cl or Br), L is a volatile ligand (e.g., an amine), x is 1-5, y is 1-5, and z is 1-5.

[0043] In one embodiment, the pressure can be between about 1 Torr and about 100 Torr. In a specific embodiment, the pressure can be between about 5 Torr and about 10 Torr. In one embodiment, in step 336, the substrate 461 can have a controlled temperature. For example, the temperature can vary between about 0° C. and about 500° C. In a specific embodiment, the temperature can vary between about 50° C. and about 150° C.

[0044] In one embodiment, the process 330 may continue at step 337 with purging the vacuum chamber. Purging with an inert gas may remove volatile by-products and residual vaporized ligands.

[0045] In one embodiment, steps 334-337 may define a cycle. This cycle may be repeated any number of times to completely (or substantially) remove the unexposed regions 462U of the metal-oxo photoresist. For example, a cycle may include a sequence including a pulse to introduce a vaporized halogenation agent into the vacuum chamber, followed by an inert purge, followed by a pulse to introduce a vaporized ligand into the vacuum chamber, followed by an inert purge. In other embodiments, a single cycle may be used. In such an embodiment, a vaporized halogenation agent soak may be introduced into the vacuum chamber, followed by an inert purge, followed by a vaporized ligand soak into the vacuum chamber, followed by an inert purge.

[0046] It has been found that the etch selectivity of the unexposed regions of the photoresist 462U relative to the exposed regions of the photoresist 462E typically increases with increasing pressure. Additionally, it has been found that increasing the substrate temperature during one or more of steps 334-337 typically increases the etch selectivity of the unexposed regions of the photoresist 462U relative to the exposed regions of the photoresist 462E.

[0047] Referring now to Figure 5, a flow diagram illustrating a process 540 for patterning a metal-oxo photoresist is shown, according to one embodiment of the present disclosure. Figures 6A-6B are corresponding cross-sectional views illustrating various processing steps in the process 540. In one embodiment, the process 540 may be similar to process 120, except that the halogenating agent is replaced with a vaporized organic acid. That is, the organic acid is vaporized into a vacuum chamber, where it reacts with either the unexposed or exposed areas of the metal-oxo photoresist to generate volatile by-products.

[0048] In one embodiment, process 540 may begin at step 541 with providing a substrate having a metal-oxo photoresist. In one embodiment, the substrate and metal-oxo photoresist may be substantially similar to the substrate and metal-oxo photoresist described above in connection with step 121 of process 120.

[0049] In one embodiment, process 540 may continue with step 542, which includes partially exposing the metal oxo photoresist to create exposed and unexposed regions. In one embodiment, the exposure process of step 542 may be substantially similar to the exposure process of step 122 of process 120. Figure 6A presents a cross-sectional view of substrate 661, exposed region 662E of photoresist, and unexposed region 662U of photoresist.

[0050] In one embodiment, process 540 may continue with step 543, which includes placing the substrate in a vacuum chamber. The vacuum chamber used in process 540 may be substantially similar to the vacuum chamber used in process 120.

[0051] In one embodiment, process 540 may continue with step 544, which includes vaporizing the organic acid in a vacuum chamber. In one embodiment, the organic acid reacts with either the unexposed regions 662U or the exposed regions 662E to generate volatile by-products. That is, a reaction between the organic acid and the unexposed regions 662U removes the unexposed regions 662U from the substrate 661 (as shown in FIG. 6B ), or a reaction between the organic acid and the exposed regions 662E removes the exposed regions 662E from the substrate 661.

[0052] In one embodiment, the organic acid can be a carboxylic acid of formula RCO2H. For example, R can be H, CH3, tBu, or iPr. In one embodiment, the by-product of the reaction is a volatile carboxylate. For example, the carboxylate can have the formula M(RC02)x, where M is a metal from the metal-oxo photoresist and R is the R used in the organic acid.

[0053] In one embodiment, the organic acid may be diluted with an inert gas. For example, an inert gas (such as Ar, N2, or He) may be used to dilute the organic acid. It has been found that the etch selectivity of the unexposed regions 662U of the photoresist relative to the exposed regions 662E of the photoresist typically increases with increasing pressure. In one embodiment, the pressure may be between about 1 Torr and about 100 Torr. In a particular embodiment, the pressure may be between about 5 Torr and about 10 Torr.

[0054] In one embodiment, in step 544, the substrate 661 may have a controlled temperature. For example, the temperature may vary between approximately 0° C. and approximately 500° C. In one particular embodiment, the temperature may vary between approximately 50° C. and approximately 150° C. It has been found that increasing the substrate temperature typically increases the etch selectivity of the unexposed regions 662U of the photoresist relative to the exposed regions 662E of the photoresist.

[0055] In one embodiment, process 540 may continue with step 545, which includes purging the vacuum chamber. Purging the vacuum chamber removes by-products from the reaction in step 544 from the vacuum chamber. In one embodiment, step 544 may be implemented as a soak followed by a single purge in step 545. In an alternative embodiment, steps 544 and 545 may define a cycle including a pulse of organic acid followed by a purge. In such an embodiment, multiple cycles may be repeated to remove unexposed regions 662U of the photoresist.

[0056] Thus, the embodiments described herein include a thermal vapor process for developing the metal-oxo photoresist. Therefore, the embodiments disclosed herein may not require a vacuum chamber capable of forming a plasma. Eliminating the plasma process also reduces damage to the metal-oxo photoresist. This is particularly beneficial when the photoresist thickness is thin (e.g., the photoresist thickness is approximately 15 nm or less). When the photoresist thickness is thin, the plasma damage can cause LER / LWR failure or even destruction of the line pattern when the pattern is transferred to the underlayer.

[0057] In addition, wet chemistry is avoided and by-products generated by the reactions disclosed herein can be destroyed in abatement systems typical of the semiconductor manufacturing industry, thus significantly reducing waste streams.Furthermore, the gas phase process allows for reduced defects and impurities in the final developed metal-oxo photoresist, especially at small feature sizes, since no wet chemistry is used.

[0058] 7 is a schematic diagram of a vacuum chamber configured to develop unexposed areas of a metal-oxo photoresist according to one embodiment of the present disclosure. Vacuum chamber 700 includes a stationary chamber 705. In one embodiment, chamber 705 can be temperature controlled; that is, the walls of chamber 705 can be actively cooled or heated in the processes disclosed herein. Substrate 710 is loaded through opening 715 and placed on a temperature controlled pedestal 720.

[0059] Process gases are supplied to the interior of the chamber 705 from gas sources 744 through respective mass flow controllers 749. In certain embodiments, a gas distribution plate 735 is provided for distribution of the process gases 744 (e.g., halogenating agents, ligands, organic acids, and / or inert gases, etc.). The chamber 705 is evacuated via an exhaust pump 755.

[0060] The vacuum chamber 700 is controlled by a controller 770. The controller 770 may include a CPU 772, a memory 773, and an I / O interface 774. The CPU 772 may perform process operations within the vacuum chamber 700 according to instructions stored in the memory 773. For example, one or more processes (such as processes 120, 330, and 540 described above) may be performed within the vacuum chamber by the controller 770.

[0061] Although the vacuum chamber 700 is described above as not having the capability to form a plasma within the chamber, it should be appreciated that embodiments of the present disclosure may also be implemented in a vacuum chamber 700 capable of generating a plasma within the chamber.

[0062] FIG. 8 illustrates an exemplary embodiment of a diagrammatic representation of a machine in a computer system 800 on 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 to (e.g., networked with) other machines in a local area network (LAN), an intranet, an extranet, or the Internet. The machine may operate in the role of 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, switch, or bridge, or any machine capable of executing a set of instructions (sequential or non-sequential) that specify operations to be performed by the machine. Further, although only a single machine is illustrated, the term "machine" should also be construed to include any collection of machines (e.g., a computer) that individually or in concert executes a set of instructions (or multiple sets of instructions) to perform any one or more of the methodologies described herein.

[0063] 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 memory 818 (e.g., a data storage device), which communicate with each other via a bus 830.

[0064] Processor 802 represents one or more general-purpose processing devices, such as a microprocessor, a central processing unit, etc. 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, or a processor implementing any other instruction set or 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, etc. Processor 802 is configured to execute processing logic 826 for performing the operations described herein.

[0065] The computer system 800 may further include a network interface device 808. The computer system 800 may also include a video display unit 810 (such as 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).

[0066] The secondary memory 818 may include a machine-accessible storage medium (or, more specifically, a computer-readable storage medium) 832 having stored thereon one or more sets of instructions (such as software 822) embodying any one or more of the methodologies or functions described herein. The software 822 may reside, in whole or at least partially, within the main memory 804 and / or the processor 802 while it is being executed by the computer system 800, with the main memory 804 and the processor 802 also constituting machine-readable storage media. The software 822 may further be transmitted or received over the network 820 via the network interface device 808.

[0067] While in an exemplary embodiment, the machine-accessible storage medium 832 is illustrated as a single medium, the term "machine-readable storage medium" should be interpreted to include a single medium or multiple media (e.g., a centralized or distributed database, 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 and that cause the machine to perform any one or more of the methodologies of this disclosure. Thus, the term "machine-readable storage medium" should be interpreted to include, but is not limited to, solid-state memories, and optical and magnetic media.

[0068] According to one embodiment of the present disclosure, a machine-accessible storage medium has instructions stored thereon that cause a data processing system to perform a method of developing metal-oxo photoresist on a substrate using a gas phase process. The method includes exposing the metal-oxo photoresist to provide exposed and unexposed regions, and placing the substrate with the exposed photoresist in a vacuum chamber. In one embodiment, a gas that reacts with the unexposed regions of the photoresist is vaporized in the vacuum chamber. For example, the reactive gas may include one or more of a halogenating agent, a ligand, and an organic acid. The reactive gas reacts with the unexposed regions of the metal-oxo photoresist to form volatile by-products. The by-products may be removed from the chamber by an inert gas purge.

[0069] Thus, a method for developing metal-oxo photoresists using a gas phase process has been disclosed.

Claims

1. 1. A method for developing a metal oxo photoresist, comprising the steps of: providing a substrate having the metal-oxo photoresist in a vacuum chamber, the metal-oxo photoresist including exposed and unexposed regions, the unexposed regions having a higher carbon concentration than the exposed regions; vaporizing a halogenating agent in the vacuum chamber, the halogenating agent reacting with the unexposed areas to generate volatile by-products; purging the vacuum chamber; and Including, The halogenating agent is methanesulfonyl chloride (CH 3 SO 2 Cl), trichloromethanesulfonyl chloride (CCl 3 SO 2 Cl), 4-toluenesulfonyl chloride (tosyl chloride), oxalyl chloride (ClCOCOCl), tert-butyl hypochlorite ((CH 3 ) 3 COCl), N-chlorophthalimide, 1,3-dichloro-5,5-dimethylhydantoin, trimethylsilyl chloride, Cl 2 , PCl 5 , BCl 3 , HBr, Br 2 , CCl 3 Br, CBr 4 , 1,2-dibromo-1,1,2,2-tetrachloroethane (Cl 2 CBrCBrCl 2 ), BBr 3 , PBr 3 , N-bromosuccinimide, N-bromoacetamide, 2-bromo-2-cyano-N,N-dimethylacetamide, 1,3-dibromo-5,5-dimethylhydantoin, 2,4,4,6-tetrabromo-2,5-cyclohexadienone, or trimethylsilyl bromide.

2. 1. A method for developing a metal oxo photoresist, comprising the steps of: providing a substrate having the metal-oxo photoresist in a vacuum chamber, the metal-oxo photoresist including exposed and unexposed regions, the unexposed regions having a higher carbon concentration than the exposed regions; vaporizing a halogenating agent in the vacuum chamber, the halogenating agent reacting with the unexposed areas to generate volatile by-products; purging the vacuum chamber; and Including, The method, wherein the halogenating agent comprises one or both of SO 2 Cl 2 (sulfuryl chloride) and SO 2 Br 2 (sulfuryl bromide).

3. 3. The method of claim 1 or 2, wherein the halogenating agent is diluted with an inert gas.

4. 1. A method for developing a metal oxo photoresist, comprising the steps of: providing a substrate having the metal-oxo photoresist in a vacuum chamber, the metal-oxo photoresist including exposed and unexposed regions, the unexposed regions having a higher carbon concentration than the exposed regions; vaporizing an organic acid in the vacuum chamber, the organic acid reacting with the unexposed areas to generate volatile by-products; purging the vacuum chamber; and A method comprising:

5. The organic acid is a carboxylic acid (RCO ２ The method according to claim 4, wherein

6. In the formula, the R group is CH ３ 6. The method of claim 5, wherein the ion exchange reaction comprises:

7. The method of claim 4 wherein the organic acid is diluted with an inert gas.

8. 1. A method for developing a metal oxo photoresist, comprising the steps of: providing a substrate having the metal-oxo photoresist in a vacuum chamber, the metal-oxo photoresist including exposed and unexposed regions; vaporizing a halogenating agent in the vacuum chamber, the halogenating agent reacting with the unexposed areas to generate volatile by-products; purging the vacuum chamber; and Including, The method of claim 1, wherein the halogenating agent comprises a metal halide having the formula MXa or MXaLb, where M is a metal or metalloid including one or more of Mo, W, Ta, Nb, Sn, V, Ti, and Si, X is a halide including one or both of Cl and Br, and L is a ligand including one or more of an alkyl group, ethylenediamine, and Cp.

9. The halogenating agent is MoCl ５ , TaCl ５ , NbCl ５ , or WCl ５ The method of claim 8 , comprising:

10. The method of claim 8, wherein a is 1 to 6 and b is 1 to 5.

11. 1. A method for developing a metal oxo photoresist, comprising the steps of: providing a substrate having the metal-oxo photoresist in a vacuum chamber, the metal-oxo photoresist including exposed and unexposed regions; vaporizing a halogenating agent in the vacuum chamber, the halogenating agent reacting with the unexposed areas to generate volatile by-products; purging the vacuum chamber; and Including, The method of claim 1, wherein the halogenating agent comprises a metal oxyhalide having the formula MOaXb or MOaXbLc, where M is a metal or metalloid including one or more of Mo, W, Ta, Nb, Sn, V, Ti, and Si, X is a halide including one or both of Cl and Br, and L is a ligand including one or more of an alkyl group, ethylenediamine, and Cp.

12. The halogenating agent is MoOCl ４ , MoO ２ C ２ , WOCl ４ , or WOCl ２ The method of claim 11 , comprising:

13. 12. The method of claim 11, wherein a is 1 to 5, b is 1 to 5, and c is 1 to 5.

14. 1. A method for developing a metal oxo photoresist, comprising the steps of: providing a substrate having the metal-oxo photoresist in a vacuum chamber, the metal-oxo photoresist including exposed and unexposed regions; vaporizing a halogenating agent in the vacuum chamber, the halogenating agent reacting with the unexposed areas to generate volatile by-products; purging the vacuum chamber; and Including, The halogenating agent is methanesulfonyl chloride (CH 3 SO 2 Cl), trichloromethanesulfonyl chloride (CCl 3 SO 2 Cl), 4-toluenesulfonyl chloride (tosyl chloride), oxalyl chloride (ClCOCOCl), tert-butyl hypochlorite ((CH 3 ) 3 COCl), N-chlorophthalimide, 1,3-dichloro-5,5-dimethylhydantoin, trimethylsilyl chloride, Cl 2 , PCl 5 , BCl 3 , HBr, Br 2 , CCl 3 Br, CBr 4 , 1,2-dibromo-1,1,2,2-tetrachloroethane (Cl 2 CBrCBrCl 2 ), BBr 3 , PBr 3 , N-bromosuccinimide, N-bromoacetamide, 2-bromo-2-cyano-N,N-dimethylacetamide, 1,3-dibromo-5,5-dimethylhydantoin, 2,4,4,6-tetrabromo-2,5-cyclohexadienone, or trimethylsilyl bromide.

15. 1. A method for developing a metal oxo photoresist, comprising the steps of: providing a substrate having the metal-oxo photoresist in a vacuum chamber, the metal-oxo photoresist including exposed and unexposed regions; vaporizing a halogenating agent in the vacuum chamber, the halogenating agent reacting with the unexposed areas to generate volatile by-products; purging the vacuum chamber; and Including, The method, wherein the halogenating agent comprises one or both of SO 2 Cl 2 (sulfuryl chloride) and SO 2 Br 2 (sulfuryl bromide).

16. 16. The method of any one of claims 8 to 15, wherein the halogenating agent is diluted with an inert gas.

17. 1. A method for developing a metal oxo photoresist, comprising the steps of: providing a substrate having the metal-oxo photoresist in a vacuum chamber; vaporizing a halogenating agent in the vacuum chamber, the halogenating agent reacting with the metal-oxo photoresist to produce volatile by-products; purging the vacuum chamber; and Including, The method wherein the halogenating agent comprises a metal halide or a metal oxyhalide.

18. The halogenating agent has the formula MX ａ Or M.X. ａ L ｂ wherein M is a metal or metalloid comprising one or more of Mo, W, Ta, Nb, Sn, V, Ti, and Si; X is a halide comprising one or both of Cl and Br; and L is a ligand comprising one or more of an alkyl group, ethylenediamine, and Cp.

19. The halogenating agent is represented by the formula MO ａ X ｂ Or M.O. ａ X ｂ L ｃ wherein M is a metal or metalloid comprising one or more of Mo, W, Ta, Nb, Sn, V, Ti, and Si; X is a halide comprising one or both of Cl and Br; and L is a ligand comprising one or more of an alkyl group, ethylenediamine, and Cp.

20. 1. A method for developing a metal oxo photoresist, comprising the steps of: providing a substrate having the metal-oxo photoresist in a vacuum chamber; vaporizing a halogenating agent in the vacuum chamber, the halogenating agent reacting with the metal-oxo photoresist to form a non-volatile product; vaporizing a ligand in the vacuum chamber, the ligand reacting with the non-volatile product to generate a volatile by-product; purging the vacuum chamber; and A method comprising:

21. 21. The method of claim 20, wherein the halogenating agent comprises a metal halide.

22. 21. The method of claim 20, wherein the halogenating agent comprises a metal oxyhalide.

23. The halogenating agent is thionyl chloride (SOCl ２ ), methanesulfonyl chloride (CH ３ SO ２ Cl), trichloromethanesulfonyl chloride (CCl ３ SO ２ Cl), 4-toluenesulfonyl chloride (tosyl chloride), oxalyl chloride (ClCOCOCl), tert-butyl hypochlorite ((CH ３ ) ３ COCl), N-chlorophthalimide, 1,3-dichloro-5,5-dimethylhydantoin, trimethylsilyl chloride, HCl, Cl ２ , PCl ５ , BCl ３ , HBr, Br ２ , CCl ３ Br, CBr ４ , 1,2-dibromo-1,1,2,2-tetrachloroethane (Cl ２ CBrCBrCl ２ ), BBr ３ , PBr ３ , N-bromosuccinimide, N-bromoacetamide, 2-bromo-2-cyano-N,N-dimethylacetamide, 1,3-dibromo-5,5-dimethylhydantoin, 2,4,4,6-tetrabromo-2,5-cyclohexadienone, or trimethylsilyl bromide.

24. 21. The method of claim 20, wherein the ligand is an amine-containing protonated ligand.

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