Acids for reactive development of metal oxide resists.

Abstract

A method for reactively developing a metal oxide resist comprises providing a gaseous weak acid to a surface of a patterned metal oxide resist, including exposed and unexposed portions, the gaseous weak acid having an acidity (pK) greater than -2 and less than about 20. a and reactively developing the patterned metal oxide resist using a selective acid-base reaction between the gaseous weak acid and the patterned metal oxide resist to form volatile products. The gaseous weak acid functions as an acid, and either the exposed or unexposed portions function as a base.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Non-Provisional Patent Application No. 17 / 871,444, filed July 22, 2022, which is incorporated herein by reference.

[0002] The present invention relates generally to systems and methods for reactive development of photoresists, and in particular embodiments, to systems and methods that utilize acid for reactive development of metal oxide resists. [Background technology]

[0003] Device fabrication of semiconductor devices can involve a series of manufacturing techniques, such as forming, patterning, and removing many layers of materials on a substrate. There is a constant and relentless pressure to improve the manufacturing processes, features, and capabilities of semiconductor devices. These improvements can require new chemistry developments as well as new advanced process control methods.

[0004] One common manufacturing technique used to pattern materials on a substrate is photolithography. During the photolithography process, a layer of photoresist is exposed to electromagnetic radiation of specific wavelengths, resulting in changes in the sensitivity of the exposed areas to the development process. Electromagnetic radiation can include visible light, but now often includes shorter wavelengths of light, such as ultraviolet (UV), deep ultraviolet (DUV), and extreme ultraviolet (EUV) light. To create a pattern in the photoresist, a lithography mask is placed between the light source and the substrate.

[0005] A development process is used to remove either the exposed areas (positive resist) or the unexposed areas (negative resist) of the photoresist, while leaving the remaining areas. The resulting photoresist pattern on the substrate is often used as an etch mask to transfer the pattern to the underlying substrate. Photoresist can be developed using a wet development process involving a solvent or a reactive development process involving a mixture of gases (including, but not limited to, so-called "dry" development processes).

[0006] Metal oxide resists (MOR) have been used in high-resolution patterning applications such as EUV lithography. Wet development of MOR films is prone to capillary-induced feature collapse at fine pitches and has low throughput because they are developed in solvents and dried using track tools.

[0007] Reactive development of MOR films prevents feature decay and has higher throughput. However, the chemistry of reactive development of MOR films is not well understood. Current compounds used to reactively develop MOR films rely on highly corrosive inorganic compounds, such as HBr. These compounds are also highly aggressive, reducing selectivity and posing serious considerations and challenges for the design and manufacture of processing tools. As a result, current techniques for reactive development of MOR films require thicker films and leave residues after the reactive development process, which reduces throughput. Therefore, improved compounds for use in reactively developing MOR films are desirable. Summary of the Invention [Means for solving the problem]

[0008] In accordance with one embodiment of the present invention, a method for reactively developing a metal oxide resist comprises providing a gaseous weak acid to a surface of a patterned metal oxide resist, including exposed and unexposed portions, the gaseous weak acid having an acidity (pK) greater than -2 and less than about 20. aand reactively developing the patterned metal oxide resist using a selective acid-base reaction between the gaseous weak acid and the patterned metal oxide resist to form volatile products. The gaseous weak acid functions as an acid, and either the exposed or unexposed portions function as a base.

[0009] According to another embodiment of the present invention, a method for reactively developing a metal oxide resist includes providing a gaseous developer to a surface of a patterned metal oxide resist, the surface including exposed and unexposed portions. The gaseous developer includes at least a partially substituted form of a compound selected from the group consisting of a carboxylic acid having the formula RCOO-H, where R is an organic group or hydrogen, an alcohol having the formula RO-H, an aromatic alcohol having the formula ArO-H, where Ar is an aromatic compound, an amine having the formula RN-H, and a borane. The method further includes reactively developing the patterned metal oxide resist using a selective acid-base reaction between the gaseous developer and the patterned metal oxide resist to form volatile products. The gaseous developer functions as an acid, and either the exposed or unexposed portions function as a base.

[0010] In accordance with yet another embodiment of the present invention, an integrated bake and reactive develop apparatus includes a vacuum chamber coupled to a pumping system, a hot plate configured to bake a substrate including a patterned metal oxide resist, and a gas inlet configured to supply a gaseous developer to develop the patterned metal oxide resist at a pressure greater than about 1 mTorr. The vacuum system includes a positive displacement pump but does not include a momentum transfer pump or a gas entrapment pump.

[0011] For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1]1 illustrates an exemplary process for reactively developing a metal oxide resist using a reactive developer comprising a gaseous weak acid in accordance with an embodiment of the present invention. [Figure 2] 1 illustrates exemplary gaseous weak acids according to embodiments of the present invention. [Figure 3] 1 illustrates exemplary gaseous weak acids that are boron-containing Lewis acids according to embodiments of the present invention. [Figure 4] 1 illustrates an exemplary integrated bake and react develop apparatus configured to develop patterned metal oxide resist at pressures above about 1 mTorr in accordance with an embodiment of the present invention. [Figure 5] 1 illustrates an example lithography process flow including a reactive develop step combined with a bake step performed in the same processing chamber in accordance with an embodiment of the present invention. [Figure 6] 1 illustrates a method for reactively developing a metal oxide resist according to an embodiment of the present invention. [Figure 7] 1 illustrates another method for reactively developing a metal oxide resist according to an embodiment of the present invention.

[0013] Corresponding numbers and symbols in different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate relevant aspects of the embodiments and are not necessarily drawn to scale. The edges of features drawn in the figures do not necessarily indicate the ends of the extents of the features. DETAILED DESCRIPTION OF THE INVENTION

[0014] The making and use of various embodiments are discussed in detail below. However, it should be recognized that the various embodiments described herein are applicable in a wide variety of specific situations. The specific embodiments discussed are merely illustrative of specific ways to make and use the various embodiments and should not be construed as limiting in scope.

[0015] Conventional reactive development of MOR films is very aggressive, which presents tool design challenges, reduces selectivity, leads to thicker resist requirements, and higher costs. Furthermore, although conventional reactive development processes have many advantages over conventional wet development processes, reactive development remains incomplete, leaving behind residues that are not present in wet development.

[0016] Conventional understanding of the reactive development process leads to the selection of a reactive developer having strong acidity. Conventional reactive development compounds used are mostly inorganic acids such as mineral acids. Halides are often considered crucial for conventional reactive development processes that require halide-based etchants. Nevertheless, these practices result in performance drawbacks for conventional reactive development processes because the reactive developers conventionally selected are too aggressive. Furthermore, highly corrosive conventional reactive development compounds are difficult to handle and require strict tool design requirements.

[0017] Low selectivity is a major drawback of conventional reactive developers. For example, due to the aggressive nature of reactive developer compounds, the selectivity is largely statistical, relying on a film structure with higher density and less accessible oxygen atoms to cause a difference in reaction rate between conventional reactive developers and the exposed parts of the MOR film compared to the exposed and unexposed parts.

[0018] The low selectivity is compensated for by tightly controlling process conditions such as temperature, pressure, gas flow rate, development time, plasma activation, and resist thickness. This in turn leads to a more stringent processing window. Also, despite tight process tuning, conventional reactive developers still do not completely develop (i.e., remove) the desired portions of the MOR film, leaving behind undesirable residues.

[0019] The inventors have discovered that the development chemistry at the surface of patterned MOR is an acid-base reaction that does not require a strong acid to be effective. Rather, the inventors have found that weak acids can also reactively develop MOR films due to the reaction's dependence on the acidity of the reactive developer compound. For example, adjusting the acidity of the reactive developer can improve the selectivity of the reaction and alter the reaction rate through a process of selective protonation of the MOR material being removed.

[0020] The embodiment MOR reactive development processes described herein can improve selectivity to removed MOR material (e.g., unexposed portions for negative resists). This increase in selectivity can, in turn, provide various benefits afforded by an expanded process window. For example, thinner MOR films may be possible, advantageously lowering costs (photoresist can be a disproportionately expensive component of the process flow) and improving throughput due to less time spent exposing and developing the MOR film. Improved selectivity also has the benefit of improving feature profile, yield, and can enable complete development of the patterned MOR, leaving little or no residue (similar to wet development processes).

[0021] The embodiments described herein may also have the advantage of enabling reactive development at higher pressures and temperatures. These pressure and temperature ranges may advantageously match much more closely the process conditions in the baking steps before and / or after the reactive development step. This may allow for a significant increase in throughput by performing baking and reactive development in the same tool, at similar pressures, and / or at similar temperatures.

[0022] The expansion of the available temperature and pressure ranges can be the result of improved selectivity. For example, improved selectivity can slow the reaction rate compared to conventional reaction development kinetics. Because reaction rate can increase with increasing temperature and pressure, a slower reaction rate can advantageously allow both temperature and pressure to be increased.

[0023] Additionally, the embodiments described herein may be less corrosive, which may have the benefit of allowing some requirements in tool design and operation to be relaxed compared to the stringent requirements of traditional reactive developers.

[0024] The embodiments provided below describe various systems and methods for reactive development of photoresist, particularly systems and methods that utilize a relatively weak acid for reactive development of MOR. The following description describes the embodiments. FIG. 1 is used to describe a process for reactively developing an embodiment MOR. Some embodiment reactive developers including a gaseous weak acid are described using FIGS. 2 and 3. An embodiment reactive developer is described using FIG. 4, while FIG. 5 is used to describe an embodiment lithography process flow that may be performed in the reactive developer. Two embodiment methods for reactively developing an MOR are described using FIGS. 6 and 7.

[0025] FIG. 1 illustrates an exemplary process for reactively developing MOR using a reactive developer comprising a gaseous weak acid in accordance with an embodiment of the present invention.

[0026] 1 , process 100 for reactively developing a MOR begins with a patterned MOR 20 having a surface 26 to be developed, as shown in step 101. The patterned MOR 20 may be disposed on a substrate 10 (e.g., a semiconductor substrate having any suitable arrangement of layers and materials). The patterned MOR 20 may be patterned using photolithography techniques to form exposed portions 22 and unexposed portions 24. For example, the photolithography techniques may be visible light photolithography, UV lithography, DUV lithography, EUV lithography, etc. In one embodiment, the patterned MOR 20 is formed by exposing a MOR film to EUV light.

[0027] The patterned MOR 20 can be any suitable MOR. For example, the MOR can include elemental metals such as tin (Sn), zinc (Zn), zirconium (Zr), indium (In), hafnium (Hf), bismuth (Bi), etc., or elemental metalloids such as germanium (Ge), antimony (An), and tellurium (Te). The MOR can form oxides when exposed to oxygen. The MOR can also include one or more moieties that promote photosensitivity. For example, the MOR can include organic moieties, such as alkyl groups, that reduce the density of the MOR before exposure to light. In one embodiment, the MOR includes Sn. In another embodiment, the MOR includes Hf. In various embodiments, the MOR includes an alkyl group having at least two carbons. In one embodiment, the alkyl group is a propyl group. In another embodiment, the alkyl group is a butyl group. MOR resists can be deposited by a variety of deposition techniques, including, but not limited to, spin coating, atomic layer deposition (ALD), molecular layer deposition (MLD), chemical vapor deposition (CVD), etc., including wet deposition and / or vacuum deposition.

[0028] Step 102 of process 100 provides a reactive developer comprising a weak gaseous acid 130 to surface 26 of patterned MOR 20. As shown in step 102, weak gaseous acid 130 begins to develop patterned MOR 20 by selectively reacting with unexposed portions 24 while minimally reacting with exposed portions 22. Weak gaseous acid 130 selectively etches unexposed portions 24 relative to exposed portions 22. For example, weak gaseous acid 130 may only slowly etch exposed portions 22 and may passivate or not react with exposed portions 22.

[0029] In the presence of gaseous weak acid 130, patterned MOR 20 is reactively developed in step 103 using a selective acid-base reaction between gaseous weak acid 130 and patterned MOR 20 to form volatile products 36 that are removed from substrate 10. During the selective acid-base reaction, gaseous weak acid 130 functions as an acid and unexposed portions 24 function as a base. In this example, MOR is a negative resist (i.e., unexposed portions 24 are removed during development). However, MOR could also be a positive resist in which exposed portions 22 are removed. In this alternative scenario, exposed portions 24 would function as a base during the selective acid-base reaction.

[0030] The gaseous weak acid 130 may have improved selectivity to the unexposed portions 24 relative to the exposed portions 22 compared to conventional reactive development techniques using strong acid compounds. This improved selectivity may have the benefit of expanding the processing window for various process parameters, such as temperature and pressure. For example, step 103 of reactively developing the patterned MOR 20 may be performed in a processing chamber at a pressure greater than about 1 mTorr (e.g., in a medium vacuum region of about 1 mTorr to about 1 Torr, in a higher low vacuum region of about 1 Torr to about 500 Torr, or atmospheric pressure).

[0031] While some conventional reactive development processes require a plasma, reactively developing the patterned MOR 20 in step 103 can advantageously be a thermal process carried out in a processing chamber where no plasma is generated within the processing chamber. In some cases, reactively developing the patterned MOR 20 in step 103 can advantageously be a thermal process carried out in a processing chamber using a weak gaseous acid activated using a remote plasma generated within a precursor chamber coupled to the processing chamber. However, it should be noted that in other situations, reactively developing the patterned MOR 20 in step 103 can advantageously include generating a plasma within the processing chamber.

[0032] The temperature process window for step 103 of reactively developing the patterned MOR 20 can be advantageously expanded by the improved selectivity of the gaseous weak acid 130. For example, reactive development of the patterned MOR 20 can be carried out at any desired temperature within the range of about −70° C. to about 400° C. This is in contrast to conventional reactive development techniques that are often limited to more moderate temperatures (e.g., above 0° C. and below 300° C., or even narrower temperature ranges). Thus, a potential advantage of the gaseous weak acid 130 is that it facilitates reactive development at more extreme temperatures. For example, in one embodiment, reactive development of the patterned MOR 20 is carried out at temperatures above 300° C. and below about 400° C. In another embodiment, reactive development of the patterned MOR 20 is carried out at temperatures below 0° C. and above about −70° C.

[0033] Another potential advantage of the expanded processing window of the weak gaseous acid 130 is that it allows optional baking steps to occur in the same processing chamber as the reactive development of the patterned MOR 20. These baking steps may include a post-exposure bake (PEB) before reactively developing the patterned MOR 20 and / or a post-development bake (PDB) after reactively developing the patterned MOR 20.

[0034] In some applications, an optional additional reactive development step may be performed after step 103. For example, step 103 may be performed such that some of the unexposed portions 24 remain, or other residues may remain. The optional additional reactive development step may be used to complete the reactive development of the patterned MOR 20.

[0035] The optional additional reactive development step may use a different gaseous weak acid, a different mixture of compounds containing a weak acid, or may incorporate a strong gaseous acid. In some embodiments, the optional additional reactive development step includes reactively developing the patterned MOR 20 using a strong gaseous acid. For example, the strong gaseous acid may be a mineral acid such as HBr. The strong acid may be more aggressive (e.g., less selective to the unexposed portions 24), but may etch faster after a significant amount of the unexposed portions 24 has been removed in the weak acid reactive development step 103, or may provide other benefits.

[0036] The reactive developer, including the gaseous weak acid 130, may be provided to the surface 26 by any suitable means. For example, the reactive developer and the gaseous weak acid 130 may be injected into a processing chamber containing the substrate 10 and the patterned MOR 20. The gaseous weak acid 130 may also be activated or generated within the processing chamber. For example, the gaseous weak acid 130 may be generated within the processing chamber from a precursor injected into the processing chamber. The gaseous weak acid 130 may also be supplied continuously or discontinuously (e.g., pumped periodically or in any pattern desired for a particular application) throughout the reactive development process.

[0037] Figure 2 illustrates an exemplary weak gaseous acid according to an embodiment of the present invention. The weak gaseous acid of Figure 2 may be a specific implementation of other weak gaseous acids described herein, such as, for example, the weak gaseous acid of Figure 1. Similarly labeled elements may be as described above.

[0038] Referring to FIG. 2, a qualitative chart 200 shows the acid dissociation constants pK a Figure 1 shows various classes of acidic compounds arranged along an acidity continuum as measured by pK. Acidic compounds are divided into two general groups: strong acids and weak acids (e.g., based on effectively complete dissociation in a solvent such as water). Strong acids have a pK of less than about -2. a It can be defined as having

[0039] Conventional reactive developers include strong gaseous acids such as halide-containing mineral acids (e.g., HBr). As mentioned above, the inventors have demonstrated that the reactive development reaction mechanism involves the use of weak gaseous acids (i.e., with a pK above -2). a We have also discovered that the reaction is an acid-base reaction that can be made more selective by utilizing a reaction developer having a pK above a certain threshold. a values (i.e., pK > 20) a This suggests that the useful range of pK for reactive development of patterned MOR films is from -2 to approximately 20. a values from which a gaseous weak acid 230 can be selected. It should be noted that not all mineral acids are strong acids under this definition. For example, hydrogen fluoride (HF) has a pK a and may be used as gaseous weak acid 230 in some embodiments.

[0040] It should be noted that, for the sake of brevity and clarity, here and below, elements following the pattern [x30] have been adopted, a convention that may be related implementations of gaseous weak acids in various embodiments. For example, gaseous weak acid 230 may be similar to gaseous weak acid 130, except where specifically noted. Similar conventions have also been adopted for other elements, as evidenced by the use of similar terms in combination with the aforementioned three-digit numbering system.

[0041] The inventors have <pK aSeveral classes of weak acids have been identified that are suitable for use as reactive developers for patterned MOR films, having acidities in the range of ≦20 (as well as other desirable properties). These include carboxylic acids having the formula RCOO-H, where R is an organic group (e.g., saturated, unsaturated, aromatic, etc.) or hydrogen; hydroxyl-containing compounds containing an OH group, such as alcohols having the formula RO-H (including the specific example of aromatic alcohol ArO-H, where Ar is an aromatic compound); and amines having the formula RN-H. Other compounds may also include thiols having the formula RS-H; amino acids having the formula R-CH(NH)COOH; nitriles having the formula R-CN (e.g., any of the acids having the formula HOCN, such as hydrocyanic acid, HCN, or cyanic / isocyanic acid, where R is hydrogen); HSCN (e.g., thiocyanic / isothiocyanic acid); hydrogen sulfide (HS); hydrogen selenide (HSe); etc. The number of carbon atoms in the R group may vary depending on the specifics of a given application. In some embodiments, the number of carbon atoms ranges from 1 to 11 carbon atoms.

[0042] Each class of compound has a pK that is typical for that class. a The preferred pK values are shown on the qualitative chart 200 as having a range of values (although not necessarily reflective of the entire set of such compounds). a An illustrative class of compounds that generally fall outside the scope includes carbon-containing compounds having the formula RC—H.

[0043] Various pK a In addition to compounds belonging to these groups having pK values, each compound also has a pK of the unsubstituted compound. a The substituents may be different in electronegativity and electron-withdrawing property, which can be varied in addition to the substituents. For example, various electron-withdrawing groups such as F, Cl, Br, I, CF3, CN, NO2, etc. can be used as substituents. In addition, the steric effect can be further utilized to change the pK of the developing gas. aThe acidity of the compound can be adjusted to both affect the pK of the developing gas and also to adjust the overall reaction feasibility between the developing gas and the MOR. In this way, the acidity of the compound can be adjusted to achieve even better selectivity and provide greater flexibility in the selection of the gaseous weak acid 230. For example, the class of aromatic alcohols advantageously has a pK of about -1 to about 11. a Similarly, simple alcohols (in the class of hydroxyl-containing compounds) can be tailored to have a pK of about 10 to about 15. a can be adjusted to have

[0044] In various embodiments, the gaseous weak acid 230 is a hydroxyl-containing compound, an aromatic alcohol, or an amine, substituted with a more electronegative substituent. For example, the more electronegative substituent can be a halogen. One particular example of this is the compound acac, which has the formula CH3C(OH)=CHC(O)CH3 (the enol tautomer making up 85% of acetylacetone (acac) solutions), and thus falls into the hydroxyl-containing class of compounds. The compound acac has a pK of approximately 8.75. a However, by replacing the hydrogen with fluorine, the compound has the formula CF3C(OH)=CHC(O)CF3 and a lower pK of about 5.35. a This results in hexafluoroacetylacetone (hfac) having the formula:

[0045] This concept can be applied to other classes of compounds as well. For example, the gaseous weak acid 230 can be an at least partially substituted simple alcohol having at least one halogen substituent. One example of this would be a fluorinated ethanol, such as trifluoroethanol. Another example would be a fluorinated propanol, such as hexafluoroisopropanol.

[0046] Figure 3 illustrates exemplary gaseous weak acids that are boron-containing Lewis acids according to embodiments of the present invention. The gaseous weak acids of Figure 3 may be specific implementations of other gaseous weak acids described herein, such as the gaseous weak acids of Figure 1. Similarly labeled elements may be as described above.

[0047] 3, table 300 shows various classes of boron-containing Lewis acids from which gaseous weak acid 330 can be selected. Compared to conventional reactive developers that use boron (e.g., BH3, BCl3), gaseous weak acid 330 has a lower acidity (e.g., -2 to about 20). In various embodiments, gaseous weak acid 330 is a Lewis acid containing boron (e.g., y≧1, z≧3, 0≦m≦z) and n>0, having the formula C n H 2n+1 alkyl groups having the formula OR where R is an organic group or hydrogen; and alkoxide groups having the formula NR where x>0. x B of at least one organic substituent X from the group consisting of amide groups having y X z-m H m is.

[0048] This includes partially substituted Lewis acids. For example, gaseous weak acid 330 can be a Lewis acid containing a boron-hydrogen bond and at least one alkyl, alkoxide, or amide substituent. Gaseous weak acid 330 can also be a Lewis acid of formula B, where y>1 and z>3. y H z The Lewis acid may be a substituted or unsubstituted Lewis acid, including higher boranes having the formula: Some examples of higher boranes are diborane (B2H6), tetraborane (B4H 10 ), pentaborane (B5H9), etc. The developer gas can also be a mixture of the aforementioned acids with different concentrations, where each component plays a specific role. One specific, non-limiting example is a developer gas with several acidic groups bound to a single molecule, such as ethylene glycol with -OH groups, which utilizes a chelating effect when bound to Sn centers.

[0049] FIG. 4 illustrates an exemplary integrated bake and react develop apparatus configured to develop patterned metal oxide resist at pressures above about 1 mTorr in accordance with an embodiment of the present invention.

[0050] 4, an integrated bake and react develop apparatus 400 includes a vacuum chamber 40 coupled to a pumping system 50 including a positive displacement pump 52. The pumping system 50 is configured to operate in a vacuum range of greater than about 1 mTorr (e.g., a medium vacuum range of about 1 mTorr to about 1 Torr, a higher low vacuum range of about 1 Torr to about 500 Torr, or atmospheric pressure), and advantageously does not require a multi-stage pumping system. That is, the pumping system 50 does not include any momentum transfer pumps or any gas entrainment pumps (typically used to achieve high vacuum and above).

[0051] A hotplate 42 (which may also be an electrostatic chuck including or coupled to a heating element) is also included in the vacuum chamber 40. The hotplate 42 is configured to support and bake the substrate 10 including the patterned MOR. The hotplate 42 may also include a heating element 44 (e.g., an electrical resistance heating element) or may be heated by any other suitable heating technique. A gas inlet 46 is configured to supply a gaseous developer (e.g., including a gaseous weak acid 130 as shown) to develop the patterned MOR at a pressure greater than about 1 mTorr.

[0052] In some embodiments, the vacuum chamber 40 may not include any plasma source configured to generate plasma within the vacuum chamber 40. In such a configuration, the reactive development process is entirely thermal, which may provide various advantages as described herein. The gaseous developer may be supplied from a precursor box 64 coupled to the gas inlet 46 of the vacuum chamber 40 (e.g., the reactive developer may be injected into the vacuum chamber 40 in the gas phase and including a weak acid). Alternatively, the precursor may be supplied into the vacuum chamber 40 from a precursor box, and the weak acid may be generated from the precursor within the vacuum chamber 40 itself.

[0053] Optionally, a remote plasma source may be coupled to the vacuum chamber 40 (e.g., to the precursor box 64) and configured to activate the gaseous developer, even for a thermal reaction development process. Alternatively, in some embodiments, a plasma source may be coupled to the vacuum chamber 40 and configured to generate a plasma within the vacuum chamber 40.

[0054] The movable lid 60 is configured to seal the vacuum chamber 40 for operation in low and medium vacuum regimes. The movable lid 60 may also be used for wafer transfer (e.g., for easy insertion and removal of substrates into and from the vacuum chamber 40). The incorporation of such a movable lid 60 may be advantageously enabled by the relaxed vacuum requirements (e.g., higher pressures) of the reactive developer used in the vacuum chamber 40. The movable lid 60, in one embodiment, may be a heated lid. Alternatively, or additionally, the vacuum chamber 40 may also include heated chamber walls 62. In some configurations (such as the configuration shown), the movable lid 60 includes a gas inlet 46 and an exhaust port 48 that are coupled to the pumping system 50. The movable lid 60 may also include a gas distribution network 66, such as the showerhead gas distribution network shown.

[0055] The integrated bake and react develop apparatus 400 can be configured to be integrated into a multi-tool processing system. For example, a multi-tool processing system may include multiple chambers, share a vacuum, and allow one or more substrates to be moved between tools without breaking vacuum. The vacuum requirements of the various tools may be similar (e.g., they may all require medium-low vacuum, atmospheric pressure, high vacuum, etc.). In one embodiment, the multi-tool processing system is a cluster tool. This may have the benefit of allowing greater control of MOR properties due to better control of queue times and atmosphere.

[0056] 5 illustrates an example lithography process flow including a reactive develop step combined with a bake step performed in the same processing chamber in accordance with an embodiment of the present invention. Lithography process flow 500 may be performed by an integrated tool, such as the integrated bake and reactive develop apparatus of FIG. 4. Similarly labeled elements may be as described above.

[0057] 5, a lithography process flow 500 includes at least one bake step and a reactive develop step 503 that occurs in the same processing chamber as the at least one bake step. This process flow can advantageously improve throughput by integrating the bake step into the same tool and develop step. The bake step can include a PEB step 511 and / or a PDB step 515. The baking conditions, tool parameters, and baking atmosphere can be the same or different from those in the reactive develop step.

[0058] As previously mentioned, reactive development step 503 may be performed at a pressure greater than about 1 mTorr (e.g., at a pressure in the medium vacuum region of about 1 mTorr to about 1 Torr, about 1 Torr to about 500 Torr, or in a higher low vacuum region such as at atmospheric pressure). Reactive development step 503 may be a thermal process performed at a higher temperature than conventional reactive development processes and in which no plasma is generated within the processing chamber. These details regarding pressure, temperature, and lack of plasma may advantageously allow for integration of the baking step with reactive development of the patterned MOR in the same tool.

[0059] The weak gaseous acid may be continuously supplied or pumped throughout the reactive development stage 503. Pumping the weak gaseous acid may have the advantage of allowing volatile compounds to be pumped away from the surface between pulses.

[0060] An expanded temperature range for the reactive development step 503 may allow for improved compatibility with the PEB step 511 and the PDB step 515, which may be performed at relatively high temperatures. Temperature ramping may take a long time compared to other processes. Therefore, similarity in temperature between the baking and developing steps may advantageously improve throughput. In one embodiment, the reactive development step 503 is performed at the same temperature as the PEB step 511 (which occurs before the reactive development step 503). In another embodiment, the reactive development step 502 is performed at the same temperature as the PDB step 515 (which occurs after the reactive development step 503).

[0061] Figure 6 illustrates a method of reactively developing a metal oxide resist according to an embodiment of the present invention. The method of Figure 6 may be combined with other methods and performed using the systems and apparatus as described herein. For example, the method of Figure 6 may be combined with any of the embodiments of Figures 1-5. While shown in a logical order, the arrangement and numbering of the steps in Figure 6 are not intended to be limiting. The method steps of Figure 6 may be performed in any suitable order or concurrently with one another, as would be apparent to one of ordinary skill in the art.

[0062] 6, a method 600 for reactively developing a MOR includes step 601 of providing a gaseous weak acid to the surface of a patterned MOR. The MOR includes exposed and unexposed portions. The gaseous weak acid has an acidity (pK) greater than -2 and less than about 20. a ). The patterned MOR is reactively developed in step 602 using a selective acid-base reaction between a gaseous weak acid and the patterned MOR to form a volatile product. The gaseous weak acid functions as an acid, and either the exposed or unexposed portions function as a base. For example, the exposed portions function as a base with respect to the positive-tone MOR, while the unexposed portions function as a base with respect to the unexposed portions.

[0063] Figure 7 illustrates another method of reactively developing a metal oxide resist according to an embodiment of the present invention. The method of Figure 7 may be combined with other methods and performed using the systems and apparatus as described herein. For example, the method of Figure 7 may be combined with any of the embodiments of Figures 1-6. While shown in a logical order, the arrangement and numbering of the steps in Figure 7 are not intended to be limiting. The method steps of Figure 7 may be performed in any suitable order or concurrently with one another, as would be apparent to one of ordinary skill in the art.

[0064] Referring to FIG. 7, a method 700 for reactively developing a MOR includes step 701 of providing a gaseous developer to the surface of the patterned MOR. As previously described, the MOR includes exposed and unexposed portions. The gaseous developer includes at least a partially substituted form of a compound selected from the group consisting of hydroxyl-containing compounds having the formula RO—H, where R is an organic group or hydrogen, aromatic alcohols having the formula ArO—H, where Ar is an aromatic compound, amines having the formula RN—H, and boranes. The MOR is reactively developed in step 702 using a selective acid-base reaction between a gaseous weak acid and the patterned MOR to form volatile products. As previously described, the gaseous developer functions as an acid, and either the exposed or unexposed portions function as a base. [Example]

[0065] Illustrative embodiments of the present invention are summarized here, with other embodiments being apparent from the entire specification and claims appended hereto.

[0066] Example 1. A method of reactively developing a metal oxide resist (MOR) comprising providing a gaseous weak acid to a surface of the patterned MOR, including exposed and unexposed portions, the gaseous weak acid having an acidity (pK) greater than -2 and less than about 20. a ), and reactively developing the patterned MOR using a selective acid-base reaction between a gaseous weak acid and the patterned MOR to form a volatile product, wherein the gaseous weak acid functions as the acid and either the exposed or unexposed portions function as the base.

[0067] Example 2. The method of example 1, wherein the gaseous weak acid comprises hydrogen fluoride.

[0068] Example 3. The method of Example 1, wherein the gaseous weak acid comprises a carboxylic acid having the formula RCOO-H, where R is an organic group or hydrogen, an alcohol having the formula RO-H, an aromatic alcohol having the formula ArO-H, where Ar is an aromatic compound, or an amine having the formula RN-H.

[0069] Example 4. The method of Example 1, wherein the gaseous weak acid comprises a thiol having the formula RS-H, where R is an organic group or hydrogen, an amino acid having the formula R-CH(NH2)COOH, a nitrile having the formula R-CN, thiocyanic acid having the formula HSCN, hydrogen sulfide (HS), or hydrogen selenide (HSe).

[0070] Example 5. A gaseous weak acid is a compound of boron and formula C, where n>1. n H 2n+1 alkyl groups having the formula OR where R is an organic group or hydrogen; and alkoxide groups having the formula NR where x>0. x and at least one organic substituent selected from the group consisting of an amide group having

[0071] Example 6. The method of Example 1, wherein the gaseous weak acid is a Lewis acid containing a boron-hydrogen bond and at least one alkyl group substituent.

[0072] Example 7. Gaseous weak acids are B with y>1 and z>3 y H z The method of Example 1, wherein the Lewis acid comprises

[0073] Example 8. A method of reactively developing a metal oxide resist (MOR), comprising: providing a gaseous developer to a surface of the patterned MOR, including exposed and unexposed portions, the gaseous developer comprising at least a partially substituted form of a compound selected from the group consisting of a carboxylic acid having the formula RCOO-H, where R is an organic group or hydrogen, an alcohol having the formula RO-H, an aromatic alcohol having the formula ArO-H, where Ar is an aromatic compound, an amine having the formula RN-H, and a borane; and reactively developing the patterned MOR using a selective acid-base reaction between the gaseous developer and the patterned MOR to form volatile products, wherein the gaseous developer functions as an acid and either the exposed or unexposed portions function as a base.

[0074] Example 9. The method of Example 8, wherein the compound is a hydroxyl-containing compound, an aromatic alcohol, or an amine, and is substituted with a more electronegative substituent.

[0075] Example 10. The method of Example 9, wherein the more electronegative substituent is a halogen.

[0076] Example 11. The method of example 10, wherein the compound is acetylacetone (acac) and the halogen is fluorine, such that the gaseous developer comprises hexafluoroacetylacetone (hfac).

[0077] Example 12. The method of Example 8, wherein the compound is a simple alcohol and the gaseous developer comprises an at least partially substituted simple alcohol having at least one halogen substituent.

[0078] Example 13. The method of example 12, wherein the gaseous developer comprises a fluorinated ethanol.

[0079] Example 14. The method of example 13, wherein the gaseous developer comprises trifluoroethanol.

[0080] Example 15. The method of example 12, wherein the gaseous developer comprises a fluorinated propanol.

[0081] Example 16. The method of example 15, wherein the gaseous developer comprises hexafluoroisopropanol.

[0082] Example 17. Compounds of formula B, where x>2 and y>0 x H y The method of Example 8, wherein the higher order borane has the formula:

[0083] Example 18. The method of any one of Examples 3 to 10, wherein the number of carbon atoms in R is in the range of 1 to 11 carbon atoms.

[0084] Example 19. The method of any one of Examples 1 and 3-18, wherein the gaseous weak acid is non-corrosive.

[0085] Example 20. The method of any one of Examples 1-19, wherein reactively developing the patterned MOR comprises reactively developing the patterned MOR in a processing chamber at a pressure greater than about 1 mTorr.

[0086] Example 21. The method of example 20, wherein the pressure is in the medium vacuum region of about 1 mTorr to about 1 Torr.

[0087] Example 22. The method of any one of Examples 1-21, wherein the reactive development of the patterned MOR is a thermal process performed in a processing chamber in which no plasma is generated in the processing chamber.

[0088] Example 23. The method of example 22, wherein the gaseous weak acid is activated using a remote plasma generated in a precursor chamber coupled to the process chamber.

[0089] Example 24. The method of any one of Examples 1-23, wherein reactive development of the patterned MOR comprises generating a plasma in the process chamber.

[0090] Example 25. The method of any one of Examples 1-24, wherein reactive development of the patterned MOR is carried out at a temperature greater than 300°C and less than about 400°C.

[0091] Example 26. The method of any one of Examples 1-24, wherein reactive development of the patterned MOR is carried out at a temperature below 0°C and above about -70°C.

[0092] Example 27. The method of any one of Examples 1-26, further comprising baking the patterned MOR in a processing chamber, wherein reactive development of the patterned MOR is performed in the same processing chamber.

[0093] Example 28. The method of Example 27, wherein baking the patterned MOR is performed as a post-exposure bake (PEB) before reactively developing the patterned MOR.

[0094] Example 29. The method of Example 28, wherein reactive development of the patterned MOR is carried out at the same temperature as the PEB.

[0095] Example 30. The method of Example 27, wherein baking the patterned MOR is performed as a post-development bake (PDB) after reactively developing the patterned MOR.

[0096] Example 31. The method of Example 30, wherein reactive development of the patterned MOR is carried out at the same temperature as the PDB.

[0097] Example 32. The method of any one of Examples 1-31, further comprising reactively developing the patterned MOR using a strong gaseous acid.

[0098] Example 33. The method of Example 32, wherein the gaseous strong acid is a mineral acid.

[0099] Example 34. The method of Example 33, wherein the mineral acid is HBr.

[0100] Example 35. The method of any one of Examples 1-34, wherein providing the gaseous weak acid to the surface of the patterned MOR comprises: introducing a precursor into a processing chamber containing the patterned MOR; and generating the gaseous weak acid from the precursor in the processing chamber.

[0101] Example 36 The method of any one of Examples 1-34, wherein providing the gaseous weak acid to the surface of the patterned MOR comprises injecting the gaseous weak acid into the processing chamber.

[0102] Example 37 The method of any one of Examples 1-36, wherein providing the gaseous weak acid to the surface of the patterned MOR comprises pumping the gaseous weak acid.

[0103] Example 38. The method of any one of Examples 1-36, wherein providing the gaseous weak acid to the surface of the patterned MOR comprises continuously supplying the gaseous weak acid.

[0104] Example 39. The method of any one of Examples 1 to 38, wherein the MOR is a positive resist.

[0105] Example 40. The method of any one of Examples 1 to 38, wherein the MOR is a negative resist.

[0106] Example 41. An integrated bake and reactive develop apparatus comprising: a vacuum chamber coupled to a pumping system including a positive displacement pump (the pumping system does not include a momentum transfer pump or a gas reservoir pump); a hot plate configured to bake a substrate including a patterned metal oxide resist (MOR); and a gas inlet configured to supply a gaseous developer at a pressure greater than about 1 mTorr to develop the patterned MOR.

[0107] Example 42. The integrated bake and react develop apparatus of example 41, wherein the vacuum chamber does not include a plasma source configured to generate plasma within the vacuum chamber.

[0108] Example 43. The integrated bake and react develop apparatus of any one of Examples 41 and 42, further comprising a remote plasma source coupled to the vacuum chamber and configured to activate the gaseous developer.

[0109] Example 44. The integrated bake and react develop apparatus of Example 43, wherein the remote plasma source is coupled to a precursor box coupled to a gas inlet.

[0110] Example 45. The integrated bake and react develop apparatus of any one of Examples 41-44, further comprising a plasma source coupled to the vacuum chamber and configured to generate a plasma within the vacuum chamber.

[0111] Example 46. The integrated bake and react develop apparatus of any one of Examples 41-45, further comprising a movable lid configured to seal the vacuum chamber for operation in low and medium vacuum regions.

[0112] Example 47. The integrated bake and react develop apparatus of example 46, wherein the movable lid is a heated lid.

[0113] Example 48. The integrated bake and react develop apparatus of any one of Examples 46 and 47, wherein the movable lid includes a gas inlet and exhaust port coupled to a pumping system.

[0114] Example 49. The integrated bake and react develop apparatus of Example 48, wherein the movable lid includes a showerhead gas delivery network.

[0115] Example 50. The integrated bake and react develop apparatus of any one of Examples 41-49, wherein the vacuum chamber comprises heated chamber walls.

[0116] Example 51. The integrated bake and react develop apparatus of example 41, wherein the integrated bake and react develop apparatus is configured to be integrated into a multi-tool processing system.

[0117] Example 52. The integrated bake and react develop apparatus of example 51, wherein the multi-tool processing system includes multiple chambers within a shared vacuum.

[0118] Example 53. The bake and react developer apparatus of Example 52, wherein the multi-tool processing system is a cluster tool.

[0119] While the present invention has been described with reference to exemplary embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the exemplary embodiments, as well as other embodiments of the invention, will be apparent to those skilled in the art upon reference to this description. It is therefore intended that the appended claims cover any such modifications or embodiments.

Claims

1. A method for reaction-developing a metal oxide resist (MOR) during a semiconductor manufacturing process, A step of providing a gaseous weak acid to the surface of a patterned MOR including exposed and unexposed areas, wherein the gaseous weak acid has an acidity (pK) greater than -2 and less than about 20. ａ ) has, and the gaseous weak acid is, Alcohols having an organic group containing a saturated carbon bonded to a hydroxyl group, Amines having nitrogen and hydrogen bonded to an organic group, and A Lewis acid comprising boron and at least one organic substituent, wherein the organic substituent is A alkyl group having the general formula C n H 2n+1, where n > 1, An alkoxide group having an alkyl group bonded to oxygen, and An amide group having nitrogen bonded to one or more organic substituents, Lewis acid, at least one from the group consisting of A step comprising a compound selected from the group consisting of, A step of reacting and developing the patterned MOR using a selective acid-base reaction between the gaseous weak acid and the patterned MOR to form a volatile product, wherein the gaseous weak acid functions as an acid, and either the exposed portion or the unexposed portion functions as a base. A method having

2. The method according to claim 1, wherein the compound is an aromatic alcohol having the general formula ArO-H, where Ar is an aromatic compound.

3. The method according to claim 1, wherein the compound is a Lewis acid comprising a boron-hydrogen bond and at least one alkyl group substituent.

4. The method according to claim 1, wherein the step of reaction-developing the patterned MOR comprises the step of reaction-developing the patterned MOR in a processing chamber at a pressure greater than approximately 1 mTorr.

5. The method according to claim 1, wherein the step of reaction-developing the patterned MOR is a thermal process carried out in a processing chamber, and no plasma is generated in the processing chamber.

6. Furthermore, the process includes a step of baking the patterned MOR in a processing chamber. The method according to claim 1, wherein the step of reaction-developing the patterned MOR is performed in the same processing chamber.

7. A method for reaction-developing a metal oxide resist (MOR) during a semiconductor manufacturing process, A step of providing a gaseous developer to the surface of a patterned MOR including exposed and unexposed areas, wherein the gaseous developer is Alcohols having an organic group with a saturated carbon bonded to a hydroxyl group, Aromatic alcohols having the general formula ArO-H, where Ar is an aromatic compound, and Amine having nitrogen and hydrogen bonded to an organic group, A step having a form in which at least a portion of a compound selected from the group consisting of the above is substituted, A step of react-developing the patterned MOR using a selective acid-base reaction between the gaseous developer and the patterned MOR to form a volatile product, wherein the gaseous developer functions as an acid, and either the exposed portion or the unexposed portion functions as a base. A method having

8. The method according to claim 7, wherein the compound is substituted with a more electronegative substituent.

9. The method according to claim 8, wherein the more electrically negative substituent is a halogen.

10. The method according to claim 9, wherein the compound is an alcohol in which at least a portion is substituted with at least one halogen substituent.

11. The method according to claim 1, wherein the compound is a simple alcohol in which at least a portion is substituted with at least one halogen substituent.

12. The method according to claim 11, wherein the compound is a fluorinated alcohol.

13. The method according to claim 9, wherein the compound is a simple alcohol that is at least partially substituted.

14. The method according to claim 13, wherein the compound is a fluorinated alcohol.

15. A method for reaction developing a metal oxide resist (MOR), A step of providing a gaseous alcohol to the surface of a patterned MOR including exposed and unexposed areas, wherein the gaseous alcohol has an organic group having a saturated carbon bonded to a hydroxyl group, A step of react-developing the patterned MOR using a selective acid-base reaction between the gaseous alcohol and the patterned MOR to form a volatile product, wherein the gaseous alcohol functions as an acid, and either the exposed portion or the unexposed portion functions as a base. A method having

16. The method according to claim 15, wherein the gaseous alcohol is a simple alcohol.

17. The method according to claim 16, wherein the simple alcohol is at least partially substituted with at least one halogen substituent.

18. The method according to claim 17, wherein the simple alcohol is fluorinated ethanol.

19. The method according to claim 17, wherein the simple alcohol is fluorinated propanol.

20. The method according to claim 15, wherein the gaseous alcohol is an aromatic alcohol having the general formula ArO-H, where Ar is an aromatic compound.

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