Hydrofluorocarbons and their use in integrated circuit manufacturing processes

Abstract

Structural analogs of 2-methyl-2-alkoxy-propane are disclosed, and more particularly, structural analogs of 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-2-alkoxy-propane, useful in integrated circuit manufacturing processes, are disclosed. Mixtures configured to etch thin films of integrated circuit materials, comprising structural analogs of 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-2-alkoxy-propane, are also disclosed. This application further describes methods for etching thin films of integrated circuit materials using the aforementioned structural analogs of 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-2-alkoxy-propane, and the application of these compounds in integrated circuit patterning processes.

Description

Cross-reference to related applications

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 593,182, filed October 25, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure generally describes structural analogs of 2-methyl-2-alkoxy-propane and their use in integrated circuit manufacturing processes, and more particularly describes structural analogs of 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-2-alkoxy-propane and their use in integrated circuit manufacturing processes. Background Technology

[0003] The lateral two-dimensional geometry of integrated circuit devices continues to decrease in size, and consequently, the surface density of these devices continues to increase. With this increased density, the chance of electrical interference (including crosstalk and parasitic capacitance) between adjacent devices increases, leading to a degraded overall integrated circuit performance. To reduce the likelihood of such electrical interference, films of low-dielectric-constant (“low-k”) insulating materials are typically placed in gaps, trenches, vias, and other surface features between adjacent devices.

[0004] However, placing low-k insulating materials in the gaps, trenches, and vias of laterally arranged integrated circuit devices also has its limitations. More specifically, the ability of such low-k insulating materials to eliminate or reduce the aforementioned electrical interference may decrease as the distance between adjacent devices decreases, and therefore the thickness of the low-k insulating material film between adjacent devices also decreases. Therefore, manufacturers have begun to focus on forming integrated circuit devices not only laterally in two dimensions, but also "vertically" in three dimensions.

[0005] As circuits are arranged in increasingly vertical orientations, the number of alternating thin-film layers of integrated circuit materials increases. For example, three-dimensional NOT AND (“3D NAND”) flash memory devices have evolved from 24-layer “stacks” of alternating thin-film integrated circuit materials to 32-layer stacks, and even to 48-layer stacks of such alternating thin-film materials. Recently, work has begun to focus on forming 96-layer and 128-layer stacks of 3D NAND flash memory devices incorporating these alternating thin-film integrated circuit materials.

[0006] To maintain the advantages of three-dimensional vertical layout circuitry, integrated circuit manufacturers require new processes and corresponding materials. One such process and material set being reviewed by integrated circuit manufacturers involves forming "channels" in 3D NAND flash memory devices. According to this technology, a channel is a roughly cylindrical conduit that extends between the bottommost surface of the bottom layer of alternating thin films of integrated circuit material in the aforementioned 3D NAND stack and the outermost surface of the topmost layer of the same stack of alternating thin film integrated circuit material. Because it is roughly cylindrical, the channel also has a diameter.

[0007] As the number of layers in 3D NAND flash memory devices increases, so does the aspect ratio of the channels. With this increased aspect ratio, manufacturers often experience more defects during channel formation, including incomplete etching, bending, and twisting. Incomplete etching occurs when the conduit cannot extend fully between the bottommost surface of an alternating layer of integrated circuit material and the outermost surface of the topmost layer of an alternating layer of the same stacked integrated circuit material. Bending occurs when the diameter of the conduit is larger than the preferred diameter at some points along the channel because etching occurs more laterally than longitudinally at those points. Twisting occurs when the channel maintains the preferred diameter but extends more laterally than longitudinally along its preferred predetermined path. These defects must be avoided when etching channels in 3D flash memory devices.

[0008] In addition to these issues, 3D NAND flash memory manufacturers are also focusing on using etched compounds with lower global warming potential than more fluorinated compounds. For example, octafluorocyclobutane is a perfluorocarbon compound, a greenhouse gas, and has a global warming potential approximately 3,200 times higher than carbon dioxide.

[0009] Octafluorocyclobutane is also a hydrofluorocarbon that can be used to etch the aforementioned channels. Therefore, integrated circuit manufacturers are looking for alternative hydrofluorocarbon compounds and mixtures that have a lower global warming potential than perfluorocarbons and also help minimize the aforementioned incomplete etching, bending, and twisting defects during channel etching in 3D NAND flash memory devices.

[0010] This disclosure aims to overcome one or more of the problems described above, and / or other problems related to the prior art. Summary of the Invention

[0011] According to a first aspect of this application, novel compounds that can be used to manufacture integrated circuits are disclosed herein. More specifically, the disclosed novel compounds include: A 1,1,1,3,3,3-Hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane; B 1,1,1,3,3,3-hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane; and C 1,1,1,3,3,3-Hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane.

[0012] According to a second aspect of this disclosure, mixtures configured for etching thin films of integrated circuit materials are disclosed herein. Such mixtures may contain a first compound structurally corresponding to formula (I): (I), Wherein n is greater than or equal to 1 and less than or equal to 3, and further wherein x is greater than or equal to 0 and less than or equal to 3. This mixture also contains a second compound comprising oxygen (O2), argon (Ar), octafluorocyclobutane (C4F8), hexafluorobutadiene (C4F6), carbonyl fluoride (COF2), difluoromethane (CH2F2), trifluoromethane (CHF3), carbon tetrafluoride (CF4), octafluorocyclopentene (C5F8), 2,3,3,3-tetrafluoroprop-1-ene (C3H2F4), hexafluoropropylene (C3F6), hexafluorocyclopropane (C3F6), 1,1,3,3,3-pentafluoropropylene (C3HF5), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3).

[0013] Although the following list is not exhaustive, the first compound of the mixture may include 1,1,1,3,3,3-hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane; 1,1,1,3,3,3-hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane; 1,1,1,3,3,3-hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane; 1,1,1,3,3,3-hexafluoro-2-methoxy-2-(trifluoromethyl)propane; 2-(difluoromethoxy)-1,1,1,3,3,3-hexafluoro-2-(trifluoromethyl)propane; and 1,1,1,3,3,3-hexafluoro-2-(trifluoromethoxy)-2-(trifluoromethyl)propane. In addition to the first and second compounds mentioned above, the mixture may further contain at least one third compound, including oxygen, argon, helium, xenon, krypton, and nitrogen. The first compound may vary from 1 volume% to less than or equal to 99 volume% of the mixture configured to etch a thin film of integrated circuit material. The composition of the thin film of integrated circuit material configured to be etched by the aforementioned mixture includes (but is not limited to) silicon, silicon oxide, silicon dioxide, silicon carbide, silicon nitride, silicon carbonitride, silicon carbide oxycarbide, silicon oxynitride, silicon carbonitride oxycarbonitride, gallium nitride, aluminum gallium nitride, gallium arsenide, aluminum gallium arsenide, indium phosphide, indium aluminum arsenide, indium gallium arsenide, silicon germanium, silicon hydrogen bromide, zinc selenide, indium tin oxide, lead zirconate titanate, molybdenum, polycrystalline silicon, photoresist, carbon hard mask, and combinations thereof.

[0014] According to a third aspect of this disclosure, a method for etching a thin film of an integrated circuit material is described herein. The method for etching the thin film includes the steps of: contacting the surface of the thin film of the integrated circuit material with a plasma containing reactive ions generated by subjecting a mixture configured to etch the thin film of the integrated circuit material to a plasma generating apparatus, thereby removing a portion of the thin film of the integrated circuit material. The mixture configured to etch the thin film may contain a first compound structurally corresponding to formula (I): (I), Wherein n is greater than or equal to 1 and less than or equal to 3, and further wherein x is greater than or equal to 0 and less than or equal to 3. This mixture also contains a second compound comprising oxygen (O2), argon (Ar), octafluorocyclobutane (C4F8), hexafluorobutadiene (C4F6), carbonyl fluoride (COF2), difluoromethane (CH2F2), trifluoromethane (CHF3), carbon tetrafluoride (CF4), octafluorocyclopentene (C5F8), 2,3,3,3-tetrafluoroprop-1-ene (C3H2F4), hexafluoropropylene (C3F6), hexafluorocyclopropane (C3F6), 1,1,3,3,3-pentafluoropropylene (C3HF5), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3).

[0015] Although the following list is not exhaustive, the first compound of the mixture may include 1,1,1,3,3,3-hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane; 1,1,1,3,3,3-hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane; 1,1,1,3,3,3-hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane; 1,1,1,3,3,3-hexafluoro-2-methoxy-2-(trifluoromethyl)propane; 2-(difluoromethoxy)-1,1,1,3,3,3-hexafluoro-2-(trifluoromethyl)propane; and 1,1,1,3,3,3-hexafluoro-2-(trifluoromethoxy)-2-(trifluoromethyl)propane. In addition to the first and second compounds mentioned above, the mixture may further contain at least one third compound including oxygen, argon, helium, xenon, krypton, and nitrogen. The first compound may vary from 1 volume% to less than or equal to 99 volume% of the mixture configured to etch a thin film of integrated circuit material. The composition of the thin film of integrated circuit material configured to be etched by the aforementioned mixture includes (but is not limited to) silicon, silicon oxide, silicon dioxide, silicon carbide, silicon nitride, silicon carbonitride, silicon carbide oxycarbide, silicon oxynitride, silicon carbonitride oxycarbonitride, gallium nitride, aluminum gallium nitride, gallium arsenide, aluminum gallium arsenide, indium phosphide, indium aluminum arsenide, indium gallium arsenide, silicon germanium, silicon hydride bromide, zinc selenide, indium tin oxide, lead zirconate titanate, molybdenum, polycrystalline silicon, photoresist, carbon hard mask, and combinations thereof.

[0016] Finally, according to a fourth aspect of the invention, a method for patterning a thin film of an integrated circuit material is also provided herein. More specifically, the method includes contacting the surface of the thin film with a plasma containing reactive ions generated by subjecting a mixture configured to etch the thin film of the integrated circuit material to a plasma generating apparatus, thereby removing a portion of the thin film and generating a pattern in the thin film of the integrated circuit material. As described in the method, at least a portion of the thin film is disposed between opposing surfaces of a substrate and a masking material layer, wherein the masking material layer includes apertures that at least partially (if not completely) pass through it and thus expose a portion of the surface of the thin film at least when the apertures completely pass through it.

[0017] The mixture configured as an etched thin film may contain a first compound that structurally corresponds to formula (I): (I), Wherein n is greater than or equal to 1 and less than or equal to 3, and further wherein x is greater than or equal to 0 and less than or equal to 3. This mixture also contains a second compound comprising oxygen (O2), argon (Ar), octafluorocyclobutane (C4F8), hexafluorobutadiene (C4F6), carbonyl fluoride (COF2), difluoromethane (CH2F2), trifluoromethane (CHF3), carbon tetrafluoride (CF4), octafluorocyclopentene (C5F8), 2,3,3,3-tetrafluoroprop-1-ene (C3H2F4), hexafluoropropylene (C3F6), hexafluorocyclopropane (C3F6), 1,1,3,3,3-pentafluoropropylene (C3HF5), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3).

[0018] Although the following list is not exhaustive, the first compound of the mixture may include 1,1,1,3,3,3-hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane; 1,1,1,3,3,3-hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane; 1,1,1,3,3,3-hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane; 1,1,1,3,3,3-hexafluoro-2-methoxy-2-(trifluoromethyl)propane; 2-(difluoromethoxy)-1,1,1,3,3,3-hexafluoro-2-(trifluoromethyl)propane; and 1,1,1,3,3,3-hexafluoro-2-(trifluoromethoxy)-2-(trifluoromethyl)propane. In addition to the first and second compounds mentioned above, the mixture may further contain at least one third compound including oxygen, argon, helium, xenon, krypton and nitrogen.

[0019] The first compound may vary from 1 volume% to less than or equal to 99 volume% of the mixture configured to etch a thin film of integrated circuit material. The composition of the integrated circuit material thin film configured to be etched by the aforementioned mixture includes (but is not limited to) silicon, silicon oxide, silicon dioxide, silicon carbide, silicon nitride, silicon carbonitride, silicon carbide oxycarbide, silicon oxynitride, silicon carbonitride oxycarbonitride, gallium nitride, aluminum gallium nitride, gallium arsenide, aluminum gallium arsenide, indium phosphide, indium aluminum arsenide, indium gallium arsenide, silicon germanium, silicon hydride bromide, zinc selenide, indium tin oxide, lead zirconate titanate, molybdenum, polysilicon, photoresist, carbon hard mask, and combinations thereof.

[0020] In a further aspect, this paper provides a method wherein the thin film is silicon dioxide or silicon nitride, and wherein, when the above conditions are true, the etch selectivity of the thin film relative to the masking material layer is greater than or equal to about 1. In this case, the masking material layer includes a metal mask, a carbon hard mask, and a photoresist. Attached Figure Description

[0021] Figure 1 This is a side view of a multilayer stack of alternating thin films of integrated circuit materials in a 3D NAND flash memory device, which depicts: (1) defect-free channels etched by the stack; (2) examples of bends and twists in channels extending by the stack; and (3) examples of incomplete etching that failed to extend by the stack.

[0022] Figure 2 This is a flowchart depicting a method configured to etch thin films of integrated circuit materials using the compounds and mixtures disclosed herein.

[0023] Figure 3 It can be used Figure 2 A schematic cross-sectional view of a wafer in a method for etching a thin film of integrated circuit material, as depicted in the figure.

[0024] Figure 4 This is a flowchart depicting a method for configuring thin films of integrated circuit materials using the compounds and mixtures disclosed herein.

[0025] Figure 5A It is available before patterning occurs. Figure 4 A schematic cross-sectional view of a wafer in a method for etching a thin film of integrated circuit material, as depicted in the figure.

[0026] Figure 5B It can be used during the patterning process Figure 4 A schematic cross-sectional view of a wafer in a method for etching a thin film of integrated circuit material, as depicted in the figure.

[0027] Figure 5C It can be used Figure 4The schematic cross-sectional view of a wafer in a method for etching a thin film of integrated circuit material, as depicted in the paper, illustrates the pattern generated in the thin film of integrated circuit material.

[0028] Figure 6A -D is a cross-sectional SEM image comparing trenches etched using a mixture of octafluorocyclobutane (C4F8) with trenches etched using mixtures disclosed herein (including mixtures using compounds 1,1,1,3,3,3-hexafluoro-2-methoxy-2-(trifluoromethyl)propane) under three different process conditions.

[0029] Figure 7A -C is a cross-sectional SEM image comparing trenches etched using a mixture of octafluorocyclobutane (C4F8) and trenches etched using a mixture of compounds 1,1,1,3,3,3-hexafluoro-2-(2,2,2-trifluoroethoxy)2-(trifluoromethyl)propane disclosed herein, under two different process conditions.

[0030] Figure 8A -D is a cross-sectional SEM image comparing trenches etched using a mixture of octafluorocyclobutane (C4F8) with trenches etched using a mixture of compounds 1,1,1,3,3,3-hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane disclosed herein under three different process conditions. Detailed Implementation

[0031] Example embodiments will be described more fully with reference to the accompanying drawings. Example embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those skilled in the art. Numerous specific details, such as examples of specific compositions, components, apparatuses, and methods, are shown to provide a thorough understanding of embodiments of this disclosure. It will be apparent to those skilled in the art that specific details are not required, example embodiments may be embodied in many different forms, and none should be construed as limiting the scope of this disclosure. In some example embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

[0032] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may also be intended to include the plural forms unless the context clearly indicates otherwise. The terms “comprising,” “containing,” “including,” and “having” are inclusive and therefore specify the presence of the stated features, elements, compositions, steps, integers, operations, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Although the open-ended term “comprising” should be understood as a non-limiting term used to describe and claim the various embodiments shown herein, in some respects it may be understood alternatively as a more restrictive and binding term, such as “consisting of” or “substantially consisting of.” Therefore, for any given embodiment describing a composition, material, component, element, feature, integer, operation, and / or process step, this disclosure also specifically includes embodiments that consist of or substantially consist of such described compositions, materials, components, elements, features, integers, operations, and / or process steps. In the case of “consisting of…”, the alternative embodiment excludes any additional composition, material, component, element, feature, integer, operation and / or process step. In the case of “consisting substantially of…”, any additional composition, material, component, element, feature, integer, operation and / or process step that substantially affects the basic and novel feature is excluded from such an embodiment. However, any composition, material, component, element, feature, integer, operation and / or process step that does not substantially affect the basic and novel feature may be included in the embodiment.

[0033] Any methods, steps, procedures, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless otherwise specified. It should also be understood that additional or alternative steps may be employed unless otherwise stated.

[0034] When a component, element, or layer is referred to as being “on,” “joined to,” “connected to,” or “coupled to” another component or layer, it may be directly on, joined to, connected to, or coupled to the other component, element, or layer, or there may be intermediate elements or layers present. Conversely, when an element is referred to as being “directly on,” “directly joined to,” “directly connected to,” or “directly coupled to” another component or layer, there may be no intermediate elements or layers present. Other terms used to describe relationships between elements should be interpreted in a similar manner (e.g., “between” vs. “directly between,” “adjacent” vs. “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0035] Although the terms first, second, third, etc., may be used herein to describe various steps, elements, components, regions, layers, and / or segments, these steps, elements, components, regions, layers, and / or segments should not be limited by these terms unless otherwise stated. These terms may be used only to distinguish one step, element, component, region, layer, or segment from another. Terms such as “first,” “second,” and other numerical terms used herein do not imply sequence or order unless the context clearly indicates otherwise. Therefore, without departing from the teachings of the exemplary embodiments, the first step, element, component, region, layer, or segment discussed below may be referred to as the second step, element, component, region, layer, or segment.

[0036] Spatial or temporal relative terms, such as “before,” “after,” “inside,” “outside,” “below,” “below,” “lower,” “above,” “upper,” etc., may be used herein to facilitate the description of the relationship between one element or feature and another element or feature as shown in the figures. In addition to the orientations depicted in the figures, spatial or temporal relative terms may be intended to cover different orientations of the apparatus or system in use or operation.

[0037] Throughout this disclosure, numerical values ​​represent approximate measurements or limitations of a range to cover minor deviations from a given value and implementations having approximately the mentioned value as well as implementations having exactly the mentioned value. Except for the working examples provided at the end of the detailed description, all numerical values ​​of parameters (e.g., quantities or conditions) in this specification (including the appended claims) should be understood to be modified in all cases by the term “about,” regardless of whether “about” actually appears before the numerical value. “About” indicates that the stated numerical value allows for some slight imprecision (having some degree close to precision in that value; approximating or reasonably close to the value; close). If the imprecision provided by “about” is not otherwise understood in this ordinary sense in the art, then “about” as used herein at least indicates the variation that may be caused by ordinary methods of measuring and using these parameters. For example, “about” can include a variation of less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in some respects, optionally less than or equal to 0.1%. [The last sentence appears to be an unrelated advertisement and has been omitted from the translation.] Furthermore, the disclosure of a scope includes the disclosure of all values ​​throughout the entire scope and the disclosure of further subdivisions of the scope, including the endpoints and sub-scopes given for the scope. Therefore, unless otherwise stated, a scope includes the endpoints and includes the disclosure of all distinct values ​​throughout the entire scope and the disclosure of further subdivisions of the scope. The disclosure of values ​​and value ranges for specific parameters (such as temperature, molecular weight, weight percentage, etc.) does not exclude other values ​​and value ranges that may be used herein. It is conceivable that specific exemplary values ​​of two or more given parameters may define the endpoints of the value ranges that can be claimed for the parameters. For example, if parameter X is exemplified herein as having a value A and also exemplified as having a value Z, then parameter X is conceivable to have a value range from about A to about Z. Similarly, the disclosure of two or more value ranges for a parameter (whether these ranges are nested, overlapping, or distinct) covers all possible combinations of the ranges of values ​​that may be claimed using the endpoints of the disclosed scope. For example, if parameter X is exemplified in this document as having a value in the range of 1-10, or 2-9, or 3-8, it is also conceivable that parameter X could have other ranges of values ​​including 1-9, 1-8, 1-3, 1-2, 2-10, 2-8, 2-3, 3-10, and 3-9.

[0038] As used herein, the terms “composition” and “material” are used interchangeably to broadly refer to a substance that contains at least preferred chemical components, elements or compounds, but may also contain other elements, compounds or substances, including trace impurities, unless otherwise stated.

[0039] Where applicable, various aspects of this disclosure will now be described with reference to the accompanying drawings and tables, unless otherwise stated, the same reference numerals denote the same elements. As mentioned above, in order to maintain the advantages of proceeding to three-dimensional vertical layout circuits, integrated circuit manufacturers require new processes and corresponding materials. One such process considered is forming channels during the creation of 3D flash memory devices, which has minimal defect formation, such as incomplete etching, bending, and twisting. Now turning to Figure 1 The figure depicts a side view of a multilayer stack 10 of alternating thin films of integrated circuit material 12 used in a 3D flash memory device. As shown, a channel 14 can extend between the bottom surface 16 of the bottom layer 18 of the alternating thin films of integrated circuit material 12 in the multilayer stack 10 and the relatively outermost surface of the top layer 22 of the alternating thin films of integrated circuit material 12 in the multilayer stack 10. Not intended to be limiting, such alternating thin films of integrated circuit material in the stack 10 often consist of a silicon nitride (i.e., Si3N4) layer followed by a silicon dioxide (i.e., SiO2) layer.

[0040] As in Figure 1As further shown, defects may occur during the formation of channel 14 in a 3D NAND flash memory device. One such defect is incomplete etching defect 24. More specifically, and as described above, incomplete etching defect 24 occurs when channel 14 fails to extend between the bottom surface 16 of the bottom layer 18 of the alternating thin films of integrated circuit material 12 in the multilayer stack 10 and the relatively outermost surface of the top layer 22 of the alternating thin films of integrated circuit material 12 in the multilayer stack 10. Another defect that integrated circuit manufacturers may experience during the formation of channel 14 in a 3D NAND flash memory device includes bending defect 26.

[0041] like Figure 1 As shown, a bending defect 26 occurs when the diameter of channel 14 is larger than the diameter of a preferred predetermined channel 14 extending at a point between the bottom surface 16 of the bottom layer 18 of the alternating thin films of integrated circuit material 12 in the multilayer stack 10 and the relatively outermost surface of the top layer 22 of the alternating thin films of integrated circuit material 12 in the multilayer stack 10. The thickness of each layer of the alternating thin films of integrated circuit material 12 in the multilayer stack 10 can be as small as a single nanometer, and the thickness can be two micrometers, three micrometers, four micrometers, five micrometers or more.

[0042] Finally, another defect that may occur in the formation of channel 14 in the 3D flash memory device is a twisting defect 28. For example... Figure 1 As seen in the diagram, a twisting defect 28 occurs when the channel 14 maintains its preferred diameter, but at least some portions of the channel 14 extend laterally relative to its preferred path 30 than longitudinally. Also as mentioned above, the manufacturer simultaneously seeks to use hydrofluorocarbons with a lower global warming potential than more conventionally used perfluorocarbons (such as octafluorocyclobutane) during the etching process of such channels 14.

[0043] Therefore, in a first aspect of this disclosure, novel and non-obvious compounds are disclosed herein. Advantageously, these compounds have low global warming potential and can be used to etch thin films, such as thin films of integrated circuit materials in multilayer stacks 10. More specifically, such compounds are represented by the following chemical formulas: A 1,1,1,3,3,3-Hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane; B 1,1,1,3,3,3-hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane; and C 1,1,1,3,3,3-Hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane.

[0044] As will be described in more detail below, the above-described compounds may be included in mixtures containing other etching materials (such as octafluorocyclobutane or hexafluorobutadiene) and are capable of etching thin films, for example... Figure 1 The thin film of integrated circuit material 12 in the multilayer stack 10 depicted in the figure.

[0045] Synthesis of compounds A, B and C Working Example 1 - Synthesis of Compound A-1,1,1,3,3,3-hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane Sodium perfluorotert-butoxide (595 mg, 2.16 mmol) was dissolved in anhydrous PhCN (5 mL), followed by the addition of CF3SO2OCH2F (441 mg, 2.42 mmol). The resulting colorless suspension was stirred at room temperature for 4 h. The product was transferred under vacuum to a separate container at 0 °C, yielding a colorless liquid with a purity of approximately 95%. Purity: 402 mg (73%). Compound A exhibits the following characteristics: 1 H NMR (400.30 MHz, CD3CN): δ 5.72 ppm (ddez, 2 J ( 19 F, 1 H) = 51.3 Hz, 5 J ( 19 F, 1 H) = 0.5 Hz, 2H, CH2F). 13 C{ 1 ¹H NMR (100.65 MHz, CD3CN): δ 120.9 (qm, 1 J ( 19 F, 13 C) = 291 Hz, 3C,CF3), 101.2 (ddez, 1 J ( 19 F, 13 C) = 227 Hz, 4 J ( 19 F, 13C) = 1.6 Hz, 1C, CH2F), 80.4 ppm(dezd, 2 J ( 19 F, 13 C) = 30.5 Hz, 3 J ( 19 F, 13 C) = 1.6 Hz 1C, C(CF3)3). 17 O NMR (54.27 MHz, CD3CN): δ 50.3 ppm (br s, 1O, OCH2F). 19 F NMR (376.66 MHz, CD3CN): δ = -71.6 (d, 5 J ( 19 F, 19 F) = 5.4 Hz, 9F, CF3),-150.6 ppm (tdez, 2 J ( 19 F, 1 H) = 51.3 Hz, 5 J ( 19 F, 19 F) = 5.4 Hz, 1F, CH2F). GC-MS (EI, 70 eV): [t = 0.48 min] m / z + = 268 [MH] + , 249 [MF] + 199[M-CF3] + . Working Example 2 - Synthesis of Compound B-1,1,1,3,3,3-hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane Perfluorotert-butanol (34.9 mL, 25 mmol) was slowly added to a stirred suspension of Cs₂CO₃ (89.6 g, 27 mmol) in benzonitrile (412 mL) at room temperature. A temperature rise of 7 K was observed. 2,2,2-trifluoroethyltrifluoromethanesulfonate (53.3 mL, 30 mmol) was added with stirring, and the mixture was heated to 70 °C for 6 h. After cooling to room temperature, the product was condensed directly from the reaction flask (heated to 50 °C) under reduced pressure (100 mbar) into a cooling trap. Yield: 86 g (91%) of volatile liquid with a boiling point of 68 °C. Compound B exhibits the following characteristics: 1 H NMR (500 MHz, CDCl3, 298 K): δ 4.34 (q, 7.7 Hz, 2H). 19 F NMR (471 MHz, CDCl3, 298 K): δ -70.5 (s, 9F), -75.2 (t, 7.2 Hz, 3F). 13 C NMR (126 MHz, CDCl3, 298 K): δ 66.2 (t, 151.4 Hz), 80.0 (s), 120.3(s), 122.2 (s). MS (EI, 70 eV): m / z (%) = 69 (40), 83 (100), 249 (30), 299 (5). Working Example 3 - Synthesis of compound C-1,1,1,3,3,3-hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane Perfluorotert-butanol (62.5 g, 37 mL, 26 mmol) was slowly added to a stirred suspension of CS₂CO₃ (95 g, 29 mmol) in benzonitrile (412 mL) at room temperature. A temperature rise of 13 K was observed. 3,3,3,2,2-pentafluoropropyltrifluoromethanesulfonate (70.6 g, 41 mL, 25 mmol) was added with stirring, and the mixture was heated to 70 °C and held for 6 h. After cooling to room temperature, water (1.25 L) was added, and the organic layer was separated. The crude product was purified by distillation after drying with Na₂SO₄. Yield: 66.8 g (73%) of volatile liquid, bp: 83 °C. Compound C exhibits the following characteristics: 1 H NMR (500 MHz, THF-d 8, 298 K): δ 4.78 (t, 11.4 Hz, 2H). 19 F NMR (471 MHz, THF- d 8, 298 K) ): δ -72.3 (s), -86.2 (s), -126.7 (t,11.4 Hz). 13 C NMR (126 MHz, THF- d 8, 298 K): δ 65.8 (tq, 30.5, 1.9 Hz), 80.6 (m), 112.8 (tq, 255.5, 38.2 Hz), 119.5 (qt, 285.9, 34.8 Hz), 121.0 (q (292.4 Hz). MS (EI, 70 eV): m / z (%) = 69 (55), 133 (20), 196 (15), 249 (95), 267 (100), 349 (15). In a second aspect, novel and non-obvious mixtures configured to have a lower global warming potential are provided, which can be used to etch thin films, such as thin films of integrated circuit material 12 in a multilayer stack 10. More specifically, such mixtures may comprise at least one first compound, which comprises a compound structurally corresponding to formula (I): (I) Where n is greater than or equal to 1 and less than or equal to 3; and Where x is greater than or equal to 0 and less than or equal to 3.

[0046] As should be understood by those skilled in the art of plasma-enhanced etching, -OCH in equation (I) n H (2n+1-x) F x The part (also known as "alkoxy group") should have at least one carbon and no more than three carbons in total. This is because, in general, alkoxy groups with more than three carbons in the backbone of 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-propane do not exist in the gaseous state at standard temperature and pressure, and are therefore likely less readily used as etchants in plasma-enhanced etching processes than those with three or fewer carbons.

[0047] Therefore, and not intended to be limiting, some 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-2-alkoxy-propane compounds represented by the above formula (where n is greater than or equal to 1 and less than or equal to 3, and where x is greater than or equal to 0 and less than or equal to 3) can be used in etching mixtures comprising: A 1,1,1,3,3,3-Hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane; B 1,1,1,3,3,3-hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane; and C 1,1,1,3,3,3-Hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane; D 1,1,1,3,3,3-hexafluoro-2-methoxy-2-(trifluoromethyl)propane; and E 2-(difluoromethoxy)-1,1,1,3,3,3-hexafluoro-2-(trifluoromethyl)propane.

[0048] Synthesis of compounds D and E Working Example 4 - Having the general formula (CF3)3COCH n F 3-n The synthesis of compounds in which n=0, 1 or 3, including compounds of D and E.

[0049] According to N. Takada, T. Abe, A. Sekiya, J. Fluorine Chem 1998, 92 These compounds are synthesized by the methods described in 167-171. As an example, compound D synthesized by this method has the following chemical properties: Its boiling point is 53℃.

[0050] 1 H NMR (500 MHz, CDCl3, 298 K): δ 3.82 (m, 3H). 19F NMR (471 MHz, CDCl3, 298 K): δ -71.1 (s). 13 C NMR (126 MHz, CDCl3, 298 K): δ 57.0 (s), 80.3 (dq, 59.1, 29.6 Hz), 120.8 (q, 292.9 Hz). MS (EI, 70 eV): m / z (%) = 69 (60), 97 (50), 131 (40), 147 (45), 181 (100), 197 (15), 231 (17). This mixture, configured to etch thin films of integrated circuit materials, contains at least one second compound in addition to the 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-2-alkoxy-propane compound described and depicted above. More specifically, such a mixture contains at least one second compound, which includes oxygen (O2), argon (Ar), octafluorocyclobutane (C4F8), hexafluorobutadiene (C4F6), carbonyl fluoride (COF2), difluoromethane (CH2F2), trifluoromethane (CHF3), carbon tetrafluoride (CF4), octafluorocyclopentene (C5F8), 2,3,3,3-tetrafluoroprop-1-ene (C3H2F4), hexafluoropropylene (C3F6), hexafluorocyclopropane (C3F6), 1,1,3,3,3-pentafluoropropylene (C3HF5), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3). Similar to the first compound described above, these second compounds can also function as materials that facilitate the etching of thin films as described herein.

[0051] In addition to the first and second compounds described above, such mixtures typically contain at least one third compound comprising oxygen, argon, helium, xenon, krypton, and nitrogen. Oxygen is typically used as a material to confine the formation of fluoropolymers generated when reactive ions of the first and second polymers described and depicted above recombine at a point along the channel 14 of the alternating thin films of the integrated circuit material 12 in the multilayer stack 10. Such accumulation of fluoropolymers at the bottom of the channel 14 may contribute to the aforementioned incomplete etching defects. Alternatively, such accumulation of fluoropolymers at different points along the channel 14 may also contribute to the formation of bending defects 26 and twisting defects 28.

[0052] As previously mentioned, the at least one third compound may also be selected from argon, helium, xenon, krypton, and nitrogen. Such compounds typically serve as carrier gases for etching processes and, more importantly, help transfer energy to the aforementioned first and second compounds and ionize them.

[0053] In a preferred embodiment of this aspect of the disclosure, the at least one first compound comprises greater than or equal to about 1% by volume and less than or equal to about 99% by volume of the mixture. In a more preferred embodiment, the at least one first compound comprises greater than or equal to about 10% by volume of the mixture and less than or equal to about 90% by volume of the mixture. In a further preferred embodiment, the at least one first compound comprises greater than or equal to about 10% by volume of the mixture and less than or equal to about 80% by volume of the mixture. In a further preferred embodiment, the at least one first compound comprises greater than or equal to about 10% by volume of the mixture and less than or equal to about 70% by volume of the mixture. In another preferred embodiment, the at least one first compound comprises greater than or equal to about 10% by volume of the mixture and less than or equal to about 60% by volume of the mixture. In yet another preferred embodiment, the at least one first compound comprises greater than or equal to about 10% by volume of the mixture and less than or equal to about 50% by volume of the mixture.

[0054] The at least one second compound and the at least one third compound constitute the balance of the volume percentages described above. More specifically, when the at least one first compound is in the range of 1% to 99% by volume of the mixture, the at least one second compound, alone or together with the at least one third compound, is in the range of 99% to 1% by volume of the mixture. When the at least one first compound constitutes a portion of the mixture greater than or equal to about 10% by volume and less than or equal to about 80% by volume, the at least one second compound, alone or together with the at least one third compound, is used in the range of 90% to 20% by volume. Additionally, in another example, when the at least one first compound constitutes a portion of the mixture greater than or equal to about 10% by volume and less than or equal to about 50% by volume, the at least one second compound, alone or together with the at least one third compound, is used in the range of 90% to 50% by volume.

[0055] As previously stated, the mixture described in the second aspect of this disclosure is configured to etch thin films of integrated circuit materials. In many cases, the thin films of integrated circuit materials comprise silicon, silicon oxide, silicon dioxide, silicon carbide, silicon nitride, silicon carbonitride, silicon oxycarbonitride, silicon oxycarbide, silicon oxycarbonitride, or combinations thereof, where appropriate. However, the mixture described in the second aspect of this disclosure can also be used to etch other thin film materials, including, but not limited to, gallium nitride, aluminum gallium nitride, gallium arsenide, aluminum gallium arsenide, indium phosphide, indium aluminum arsenide, indium gallium arsenide, silicon germanium, silicon hydride bromide, zinc selenide, indium tin oxide, lead zirconate titanate, molybdenum, polysilicon, photoresist, carbon hard masks, and combinations thereof.

[0056] Industrial applicability In practice, the compounds and mixtures described above have been found to be useful in many integrated circuit manufacturing processes, including but not limited to etching thin films, such as in plasma-enhanced etching processes. Figure 1 The thin film of the integrated circuit material 12 in the multilayer stack 10 is illustrated. Therefore, in the third aspect of this disclosure, and as... Figure 2 The diagram illustrates a flowchart depicting a method configured to etch thin films of integrated circuit materials using the compounds and mixtures disclosed herein. As seen in step 110, a wafer comprising a thin film of integrated circuit material disposed thereon can be positioned inside the reaction chamber of a plasma-enhanced etching apparatus.

[0057] Now go to Figure 3 A cross-sectional schematic diagram of an example wafer 210 that can be used in step 110 is disclosed, and Figure 2 Any remaining steps described herein. As seen herein, a wafer may consist of a substrate 212 having a thin film of integrated circuit material 214 disposed thereon. Substrate 212 comprises one of silicon (e.g., monocrystalline silicon) or polycrystalline silicon. In many cases, the thin film of integrated circuit material 214 comprises silicon oxide, silicon dioxide, silicon carbide, silicon nitride, silicon carbonitride, silicon oxycarbonitride, silicon oxycarbide, silicon oxycarbonitride, and combinations thereof where appropriate. In most cases, the thin film 214 of integrated circuit material is one of silicon dioxide or silicon nitride.

[0058] Alternatively or optionally, the thin film of the integrated circuit material 214 disposed on the wafer 210 may also include gallium nitride, aluminum gallium nitride, gallium arsenide, aluminum gallium arsenide, indium phosphide, indium aluminum arsenide, indium gallium arsenide, silicon germanium, silicon hydride bromide, zinc selenide, indium tin oxide, lead zirconate titanate, molybdenum, polysilicon, photoresist, carbon hard mask, and combinations thereof. Additionally, the thin film of the integrated circuit material 214 includes a surface 216 that can be contacted by a plasma containing reactive ions configured to etch a mixture of the thin films of the integrated circuit material 214. Although Figure 3 As not shown herein, the wafer is intended to include thin films of more than one integrated circuit material, such as alternating thin films of the same and / or different materials as described herein, disposed on a substrate.

[0059] Now back Figure 2 And at the same time review Figure 3 In step 112, the mixture configured to etch the thin film of integrated circuit material 214 can flow into a plasma-enhanced etching chamber. In a first case, the mixture may contain at least one first compound, which comprises a compound structurally corresponding to formula (I): (I) Where n is greater than or equal to 1 and less than or equal to 3; and Where x is greater than or equal to 0 and less than or equal to 3.

[0060] As those skilled in the art of plasma-enhanced etching should understand, the alkoxy group in formula (I) should have at least one carbon atom and a total of no more than three carbon atoms. This is due to the fact that, generally speaking, alkoxy groups with more than three carbon atoms in the backbone of 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-propane do not exist in the gaseous state at standard temperatures and pressures, and are therefore likely less readily used as etchants in plasma-enhanced etching processes than those groups with three or fewer carbon atoms.

[0061] Therefore, some 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-2-alkoxy-propane compounds represented by the above formula (where n is greater than or equal to 1 and less than or equal to 3, and x is greater than or equal to 0 and less than or equal to 3) that can be used in etching mixtures include: A 1,1,1,3,3,3-Hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane; B 1,1,1,3,3,3-Hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane; C 1,1,1,3,3,3-Hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane; D 1,1,1,3,3,3-Hexafluoro-2-methoxy-2-(trifluoromethyl)propane; or E 2-(difluoromethoxy)-1,1,1,3,3,3-hexafluoro-2-(trifluoromethyl)propane.

[0062] In addition to the 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-2-alkoxy-propane compound described and depicted above, this mixture configured to etch the thin film of the integrated circuit material further comprises at least one second compound. More specifically, this mixture comprises at least one second compound, which includes oxygen (O2), argon (Ar), octafluorocyclobutane (C4F8), hexafluorobutadiene (C4F6), carbonyl fluoride (COF2), difluoromethane (CH2F2), trifluoromethane (CHF3), carbon tetrafluoride (CF4), octafluorocyclopentene (C5F8), 2,3,3,3-tetrafluoroprop-1-ene (C3H2F4), hexafluoropropylene (C3F6), hexafluorocyclopropane (C3F6), 1,1,3,3,3-pentafluoropropylene (C3HF5), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3). Like the first compound, these second compounds can also be used as materials that facilitate the etching of the thin film of the integrated circuit material 212.

[0063] In addition to the first and second compounds described above, such a mixture may further contain at least one third compound comprising oxygen, argon, helium, xenon, krypton, and nitrogen. Oxygen is conventionally used as a material to limit the formation of fluoropolymers during the reactive ionic recombination of the first and second compounds described above. As previously mentioned, at least one third compound may also be selected from argon, helium, xenon, krypton, and nitrogen. Such compounds can act as carrier gases for etching processes and, more importantly, help transfer energy to and ionize the aforementioned first and second compounds.

[0064] In a preferred embodiment of the third aspect of this disclosure, at least one first compound comprises more than or equal to about 1% by volume and less than or equal to about 99% by volume of the mixture. In a more preferred embodiment, at least one first compound comprises more than or equal to about 10% by volume of the mixture and less than or equal to about 90% by volume of the mixture. In a further preferred embodiment, at least one first compound comprises more than or equal to about 10% by volume of the mixture and less than or equal to about 80% by volume of the mixture. In a further preferred embodiment, at least one first compound comprises more than or equal to about 10% by volume of the mixture and less than or equal to about 70% by volume of the mixture. In another preferred embodiment, at least one first compound comprises more than or equal to about 10% by volume of the mixture and less than or equal to about 60% by volume of the mixture. In yet another preferred embodiment, at least one first compound comprises more than or equal to about 10% by volume of the mixture and less than or equal to about 50% by volume of the mixture.

[0065] At least one second compound and at least one third compound constitute the balance of the volume percentages described above. More specifically, when at least one first compound is in the range of 1% to 99% by volume of the mixture, then at least one second compound, alone or together with at least one third compound, is in the range of 99% to 1% by volume of the mixture. When at least one first compound accounts for more than or equal to about 10% by volume and less than or equal to about 80% by volume of the mixture, then at least one second compound, alone or together with at least one third compound, is in the range of 90% to 20% by volume of the mixture. Additionally, in another example, when at least one first compound accounts for more than or equal to about 10% by volume and less than or equal to about 50% by volume of the mixture, then at least one second compound, alone or together with at least one third compound, is in the range of 90% to 50% by volume of the mixture.

[0066] Review again Figure 2 , refer to Figure 3 In step 114, a plasma generator electronically coupled to the reaction chamber of the plasma-enhanced etching apparatus can be turned on, thereby generating a plasma containing reactive ions, which is configured to etch a thin film of integrated circuit material 214 inside the reaction chamber of the plasma-enhanced etching apparatus. Figure 2 In step 116 described in the text, Figure 3 The surface 216 can be contacted with a plasma containing reactive ions in a mixture of thin films configured to etch the thin film 214 on the wafer 210, thereby removing a portion of the thin film 214 disposed on the wafer 210.

[0067] According to a fourth aspect of the invention disclosed herein, a method for patterning thin films of integrated circuit materials is disclosed. Now turning to... Figure 4 At the same time, it also reviewed Figures 5A-5C In step 310, the wafer 410 can be positioned inside the reaction chamber of the plasma-enhanced etching apparatus. For example... Figures 5A to 5C As shown in each of them, the wafer 410 may consist of a substrate 420 having a thin film of integrated circuit material 430 disposed thereon between the opposing surfaces 440 of the substrate 420 and the masking material layer 450.

[0068] Substrate 420 comprises silicon (e.g., monocrystalline silicon) or polycrystalline silicon. In many cases, the thin film of integrated circuit material 430 comprises silicon oxide, silicon dioxide, silicon carbide, silicon nitride, silicon carbonitride, silicon oxycarbonitride, silicon oxycarbide, silicon oxycarbonitride, and, where appropriate, combinations thereof. In most cases, the thin film of integrated circuit material 430 is either silicon dioxide or silicon nitride.

[0069] Alternatively or additionally, the thin film of the integrated circuit material 430 disposed between the opposing surfaces 440 may also comprise gallium nitride, aluminum gallium nitride, gallium arsenide, aluminum gallium arsenide, indium phosphide, indium aluminum arsenide, indium gallium arsenide, silicon germanium, silicon hydride bromide, zinc selenide, indium tin oxide, lead zirconate titanate, molybdenum, polysilicon, and combinations thereof. Furthermore, the masking material layer 450 may include a carbon hard mask, a photoresist, a metal mask, and combinations thereof. Finally, as... Figure 5A As seen in the diagram, the masking material layer 450 includes one or more holes 460 defined at least partially therethrough. In another example, one or more holes 460 may be defined entirely through the masking material layer 450. As will be understood by those skilled in the art, the holes 460 define a pattern in the thin film of the etched integrated circuit material 430.

[0070] Back Figure 4 And at the same time, still review Figure 5A and Figure 5B In step 312, the mixture configured to etch the thin film of integrated circuit material 430 can flow into the plasma-enhanced etching chamber. In a first case, the mixture may contain at least one first compound, which comprises a compound structurally corresponding to formula (I): (I) Where n is greater than or equal to 1 and less than or equal to 3; and Where x is greater than or equal to 0 and less than or equal to 3.

[0071] As understood by those skilled in the art of plasma-enhanced etching, alkoxy groups should have at least one carbon atom and no more than three carbon atoms in total. This is due to the fact that, generally speaking, alkoxy groups with more than three carbon atoms in the backbone of 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-propane do not exist in the gaseous state at standard temperatures and pressures, and therefore may not be as readily used as etchants in plasma-enhanced etching processes as those groups with three or fewer carbon atoms.

[0072] Therefore, some 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-2-alkoxy-propane compounds that can be used in etching mixtures, represented by the above formula (where n is greater than or equal to 1 and less than or equal to 3, and x is greater than or equal to 0 and less than or equal to 3), include: A 1,1,1,3,3,3-Hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane; B 1,1,1,3,3,3-Hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane; C 1,1,1,3,3,3-Hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane; D 1,1,1,3,3,3-Hexafluoro-2-methoxy-2-(trifluoromethyl)propane; or E 2-(difluoromethoxy)-1,1,1,3,3,3-hexafluoro-2-(trifluoromethyl)propane.

[0073] In addition to the 1,1,1,3,3,3-hexafluoro-2-trifluoromethyl-2-alkoxy-propane compound described and depicted above, this mixture configured to etch the thin film of the integrated circuit material further comprises at least one second compound. More specifically, this mixture comprises at least one second compound, which includes oxygen (O2), argon (Ar), octafluorocyclobutane (C4F8), hexafluorobutadiene (C4F6), carbonyl fluoride (COF2), difluoromethane (CH2F2), trifluoromethane (CHF3), carbon tetrafluoride (CF4), octafluorocyclopentene (C5F8), 2,3,3,3-tetrafluoroprop-1-ene (C3H2F4), hexafluoropropylene (C3F6), hexafluorocyclopropane (C3F6), 1,1,3,3,3-pentafluoropropylene (C3HF5), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3). Like the first compound, these second compounds can also be used as materials that facilitate the etching of the thin film of integrated circuit material 430.

[0074] In addition to the first and second compounds described above, such a mixture may further contain at least one third compound comprising oxygen, argon, helium, xenon, krypton, and nitrogen. Oxygen is conventionally used as a material to limit the formation of fluoropolymers during the reactive ionic recombination of the first and second compounds described and depicted above. As previously mentioned, at least one third compound may also be selected from argon, helium, xenon, krypton, and nitrogen. Such compounds typically serve as carrier gases for etching processes and, more importantly, help transfer energy to and ionize the aforementioned first and second compounds.

[0075] In a preferred embodiment of the third aspect of this disclosure, at least one first compound comprises more than or equal to about 1% by volume and less than or equal to about 99% by volume of the mixture. In a more preferred embodiment, at least one first compound comprises more than or equal to about 10% by volume of the mixture and less than or equal to about 90% by volume of the mixture. In a further preferred embodiment, at least one first compound comprises more than or equal to about 10% by volume of the mixture and less than or equal to about 80% by volume of the mixture. In a further preferred embodiment, at least one first compound comprises more than or equal to about 10% by volume of the mixture and less than or equal to about 70% by volume of the mixture. In another preferred embodiment, at least one first compound comprises more than or equal to about 10% by volume of the mixture and less than or equal to about 60% by volume of the mixture. In yet another preferred embodiment, at least one first compound comprises more than or equal to about 10% by volume of the mixture and less than or equal to about 50% by volume of the mixture.

[0076] At least one second compound and at least one third compound constitute the balance of the volume percentages described above. More specifically, when at least one first compound is in the range of 1% to 99% by volume of the mixture, then at least one second compound, alone or together with at least one third compound, is in the range of 99% to 1% by volume of the mixture. When at least one first compound constitutes a portion of the mixture greater than or equal to about 10% by volume and less than or equal to about 80% by volume of the mixture, then at least one second compound, alone or together with at least one third compound, is in the range of 90% to 20% by volume of the mixture. Additionally, in another example, when at least one first compound constitutes a portion of the mixture greater than or equal to about 10% by volume and less than or equal to about 50% by volume of the mixture, then at least one second compound, alone or together with at least one third compound, is in the range of 90% to 50% by volume of the mixture.

[0077] Next, in step 314, a plasma generation device electronically coupled to the reaction chamber of the plasma-enhanced etching apparatus can be turned on, thereby generating a plasma containing reactive ions, which is configured to etch a thin film of integrated circuit material 430 inside the reaction chamber of the plasma-enhanced etching apparatus. Figure 4 In step 316 described in the text, it is possible to make Figure 5A and 5BOne or more holes 460 shown are contacted with a plasma containing reactive ions configured to etch a mixture of thin films of integrated circuit material 430, thereby removing any residual masking material layer 440 and thus fully defining one or more holes 460 through the entire masking material layer 440, thereby exposing the surface 470 of the thin film of integrated circuit material 430 with shape and size consistent with the associated holes 460.

[0078] In step 318, as Figure 4 As shown, Figure 5B Surface 470 can be contacted with a plasma containing reactive ions, configured to etch a mixture of thin films of integrated circuit material 430, thereby removing a portion of the thin film disposed on wafer 410. For example... Figure 5C As shown, the removal of this material 430 in step 318 creates a pattern 480 in the thin film of the integrated circuit material 430. As understood by those skilled in the art of dry etching, the pattern 480 created in this process corresponds in shape and size to the vias 460 coupled to it in the masking material layer 440. Some common patterns 480 etched into the thin film of the integrated circuit material 430 include gaps, trenches, and vias that can subsequently be backfilled with a low-k material. Alternatively, the pattern 480 may include the above. Figure 1 Channel 14 of the 3D flash memory device depicted in the image.

[0079] Using the mixtures described herein advantageously results in thin film etching and patterning with the desired selectivity. For example, in the case where the thin film comprises silicon dioxide or silicon nitride, the mixture can have an etching selectivity of the thin film to the masking material layer (e.g., metal mask, carbon hard mask, photoresist) greater than or equal to about 1.

[0080] For illustrative and descriptive purposes, the foregoing description of embodiments has been provided. It is not intended to be exhaustive or limiting of this disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable where applicable and can be used in chosen embodiments, even if not specifically shown or described. It can also be varied in many ways. Such variations should not be considered as departing from this disclosure, and all such modifications are intended to be included within the scope of this disclosure.

[0081] Patterning methods All patterning tests were performed using a PlasmaTherm APEX SLR ICP 200mm reaction chamber. The plasma generator, electronically coupled to the reaction chamber, was an inductively coupled plasma generator with a 2 MHz top electrode source and a 13.56 MHz biased bottom electrode / base. The top electrode power could be varied between 0 watts (“W”) and approximately 2000 W, while the bottom electrode / base power could be varied between 0 W and approximately 600 W. The bottom electrode / base temperature could be varied between approximately -40°C and 250°C to evaluate the effect of the reduced temperature on pattern formation. The pressure in the reaction chamber could be varied between approximately 1 mTorr and 100 mTorr, and the flow rate of the mixture configured to etch the thin film of the integrated circuit material could be varied between 1 and 500 standard cubic centimeters per minute (“sccm”). Oxygen, argon, or a mixture of oxygen and argon were typically flowed into the reaction chamber as part of the mixture configured to etch the thin film of the integrated circuit material, while up to three other gases could be simultaneously flowed into the reaction chamber along with oxygen and / or argon to aid in patterning in the thin film of the integrated circuit material.

[0082] Working Example 5 - Generation of trench-1,1,1,3,3,3-hexafluoro-2-methoxy-2-(trifluoromethyl)propane using compound D: D Based on blanket-covered wafer screening DOE, several process conditions were selected for patterned wafer etching and compared with the best known method (“BKM”) conditions for octafluorocyclobutane (C4F8). BKM is a term in the art. The following table shows the C4F8 BKM conditions: The table below shows three process conditions for running compound D on a patterned wafer: All patterned etching in the table above was performed at a room temperature of 60°C and an electrode temperature of 25°C. The table below shows a comparison of the etching profiles under C4F8BKM conditions with three process conditions for compound D. In all the tables below, CD is defined as the critical dimension, which is a term used in the art.

[0083] Data shows that compound D exhibits a patterned silicon oxide etch rate up to 25% higher than C4F8, with SiO2 showing up to 90% better selectivity relative to the photoresist. Optimized condition P12 also demonstrates better CD control on patterned wafers, with a 10% improvement in the bottom / top CD ratio. Overall, compound D exhibits a higher patterned etch rate with improved selectivity and CD control compared to C4F8.

[0084] Figure 6A Cross-sectional SEM images of trenches produced by P3, P7, and P7 processes of C4F8BKM and Compound D are shown in -D. The SEM images reveal deeper etched trenches in Compound D with more residual photoresist, demonstrating a higher patterned SiO2 etch rate and selectivity than C4F8. The etch distribution, particularly the optimized PL2 wafer, also shows straighter sidewalls than C4F8.

[0085] Working Example 6 - Generation of trench-1,1,1,3,3,3-hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane using compound B B Based on blanket-covered wafer screening DOE, several process conditions were selected for patterned wafer etching and compared with the C4F8BKM conditions. The table below shows the C4F8BKM conditions: The table below shows two process conditions for Compound B running on a patterned wafer: All patterned etching was performed at a room temperature of 60°C and an electrode temperature of 25°C. The following table compares the etching profiles under the C4F8BKM conditions with those under compound B: Data shows that, for both process conditions, compound B exhibits a significantly higher silicon oxide patterning etch rate than C4F8, and a 58% higher rate for wafer P7. SiO2 also shows up to 16% higher selectivity relative to the photoresist compared to C4F8. Compound B also demonstrates better CD control, as evidenced in cross-sectional SEM images of trenches produced by C4F8BKM, P5, and P7 processes. Figure 7A -C is shown.

[0086] like Figure 7A As shown in -C, the SEM etch profile using compound B, compared to C4F8, reveals much deeper etch trenches and a similar amount of residual photoresist. Furthermore, the etch profile exhibits straighter sidewalls than C4F8, particularly for wafer P7. The data also indicate that the higher molecular weight of compound B (318 g / mol) compared to compound D (250 g / mol) results in a higher patterning etch rate.

[0087] Working Example 7 - Generation of trench-1,1,1,3,3,3-hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane using compound C C Based on blanket-covered wafer screening DOE, several process conditions were selected for patterned wafer etching and compared with the C4F8BKM conditions. The table below shows the C4F8BKM conditions: The table below shows three process conditions for running compound C on a patterned wafer. All patterned etching was performed at a room temperature of 60°C and an electrode temperature of 25°C. The following table compares the etching profiles under the BKM conditions with those under compound C under three different process conditions: Data shows that compound C exhibits a patterned silicon oxide etch rate up to 18% higher than C4F8, with similar selectivity of SiO2 relative to photoresist. Condition P4 also shows better CD control on patterned wafers, with a 40% improvement in the bottom / top CD ratio, but a lower etch rate. Overall, compound F exhibits a higher patterned etch rate compared to C4F8, with similar selectivity and improved CD control.

[0088] Figure 8A -D shows cross-sectional SEM images of the trenches produced by C4F8BKM compared to the P3, P4, and P7 trenches produced by compound C. The SEM data show that the trenches etched with compound C are deeper for conditions P3 and P7, and also have much better CD control and straighter sidewalls for condition P4.

[0089] The foregoing description is merely representative, and modifications may be made to aspects of the invention disclosed herein without departing from the scope of this disclosure. Therefore, such modifications fall within the scope of this disclosure and are intended to fall within the appended claims.

Claims

1. A compound represented by the following formula: A 1,1,1,3,3,3-Hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane.

2. A compound represented by the following formula: B 1,1,1,3,3,3-Hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane.

3. A compound represented by the following formula: C 1,1,1,3,3,3-Hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane.

4. A mixture configured to etch a thin film of an integrated circuit material, comprising: The first compound comprises compounds that structurally correspond to formula (I): （I） Where n is greater than or equal to 1 and less than or equal to 3; and Where x is greater than or equal to 0 and less than or equal to 3; and The second compound contains oxygen (O2), argon (Ar), octafluorocyclobutane (C4F8), hexafluorobutadiene (C4F6), carbonyl fluoride (COF2), difluoromethane (CH2F2), trifluoromethane (CHF3), carbon tetrafluoride (CF4), octafluorocyclopentene (C5F8), 2,3,3,3-tetrafluoroprop-1-ene (C3H2F4), hexafluoropropylene (C3F6), hexafluorocyclopropane (C3F6), 1,1,3,3,3-pentafluoropropylene (C3HF5), sulfur hexafluoride (SF6), or nitrogen trifluoride (NF3).

5. The mixture according to claim 4, wherein the first compound comprises: A 1,1,1,3,3,3-Hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane; B 1,1,1,3,3,3-Hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane; C 1,1,1,3,3,3-Hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane; D 1,1,1,3,3,3-Hexafluoro-2-methoxy-2-(trifluoromethyl)propane; or E 2-(difluoromethoxy)-1,1,1,3,3,3-hexafluoro-2-(trifluoromethyl)propane.

6. The mixture according to claim 4, wherein the second compound comprises oxygen (O2) or argon (Ar).

7. The mixture according to claim 4 further comprises a third compound comprising oxygen, argon, helium, xenon, krypton, or nitrogen.

8. The mixture according to claim 4, wherein the first compound comprises more than or equal to about 1% by volume of the mixture and less than or equal to about 99% by volume of the mixture.

9. The mixture of claim 4, wherein the thin film of the integrated circuit material comprises silicon, silicon oxide, silicon dioxide, silicon carbide, silicon nitride, silicon carbonitride, silicon carbide oxycarbide, silicon oxynitride, silicon carbonitride oxycarbonitride, gallium nitride, aluminum gallium nitride, gallium arsenide, aluminum gallium arsenide, indium phosphide, indium aluminum arsenide, indium gallium arsenide, silicon germanium, silicon hydride bromide, zinc selenide, indium tin oxide, lead zirconate titanate, molybdenum, polycrystalline silicon, photoresist, carbon hard mask, or a combination thereof.

10. A method for etching a thin film of an integrated circuit material, comprising: A portion of the thin film of the integrated circuit material is removed by contacting the surface of the film with a plasma containing reactive ions generated by subjecting a mixture configured to etch the thin film of the integrated circuit material to a plasma generator. The mixture comprises: The first compound comprises compounds that structurally correspond to formula (I): （I） Where n is greater than or equal to 1 and less than or equal to 3; and Where x is greater than or equal to 0 and less than or equal to 3; and The second compound contains oxygen (O2), argon (Ar), octafluorocyclobutane (C4F8), hexafluorobutadiene (C4F6), carbonyl fluoride (COF2), difluoromethane (CH2F2), trifluoromethane (CHF3), carbon tetrafluoride (CF4), octafluorocyclopentene (C5F8), 2,3,3,3-tetrafluoroprop-1-ene (C3H2F4), hexafluoropropylene (C3F6), hexafluorocyclopropane (C3F6), 1,1,3,3,3-pentafluoropropylene (C3HF5), sulfur hexafluoride (SF6), or nitrogen trifluoride (NF3).

11. The method of claim 10, wherein the first compound comprises: A 1,1,1,3,3,3-Hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane; B 1,1,1,3,3,3-Hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane; C 1,1,1,3,3,3-Hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane; D 1,1,1,3,3,3-Hexafluoro-2-methoxy-2-(trifluoromethyl)propane; or E 2-(difluoromethoxy)-1,1,1,3,3,3-hexafluoro-2-(trifluoromethyl)propane.

12. The method of claim 10, wherein the mixture further comprises a third compound comprising oxygen, argon, helium, xenon, krypton, or nitrogen.

13. The method of claim 10, wherein the first compound comprises more than or equal to about 1% by volume of the mixture and less than or equal to about 99% by volume of the mixture.

14. The method of claim 10, wherein the integrated circuit material thin film comprises silicon, silicon oxide, silicon dioxide, silicon carbide, silicon nitride, silicon carbonitride, silicon carbide oxycarbide, silicon oxynitride, silicon carbonitride oxycarbonitride, gallium nitride, aluminum gallium nitride, gallium arsenide, aluminum gallium arsenide, indium phosphide, indium aluminum arsenide, indium gallium arsenide, silicon germanium, silicon hydride bromide, zinc selenide, indium tin oxide, lead zirconate titanate, molybdenum, polycrystalline silicon, photoresist, carbon hard mask, or a combination thereof.

15. A method for patterning a thin film of an integrated circuit material, comprising: The surface of the thin film is brought into contact with a plasma containing reactive ions generated by subjecting a mixture of thin films configured to etch the integrated circuit material to a plasma generator, thereby removing a portion of the thin film and creating a pattern in the thin film of the integrated circuit material; At least a portion of the thin film is disposed between the opposing surfaces of the substrate and the masking material layer, wherein the masking material layer includes pores defined therethrough and thereby exposing a portion of the surface of the thin film; The mixture comprises: The first compound comprises compounds that structurally correspond to formula (I): （I） Where n is greater than or equal to 1 and less than or equal to 3; and Where x is greater than or equal to 0 and less than or equal to 3; and The second compound contains oxygen (O2), argon (Ar), octafluorocyclobutane (C4F8), hexafluorobutadiene (C4F6), carbonyl fluoride (COF2), difluoromethane (CH2F2), trifluoromethane (CHF3), carbon tetrafluoride (CF4), octafluorocyclopentene (C5F8), 2,3,3,3-tetrafluoroprop-1-ene (C3H2F4), hexafluoropropylene (C3F6), hexafluorocyclopropane (C3F6), 1,1,3,3,3-pentafluoropropylene (C3HF5), sulfur hexafluoride (SF6), or nitrogen trifluoride (NF3).

16. The method of claim 15, wherein the first compound comprises: A 1,1,1,3,3,3-Hexafluoro-2-(fluoromethoxy)-2-(trifluoromethyl)propane; B 1,1,1,3,3,3-Hexafluoro-2-(2,2,2-trifluoroethoxy)-2-(trifluoromethyl)propane; C 1,1,1,3,3,3-Hexafluoro-2-(2,2,3,3,3-pentafluoropropoxy)-2-(trifluoromethyl)propane; D 1,1,1,3,3,3-Hexafluoro-2-methoxy-2-(trifluoromethyl)propane; or E 2-(difluoromethoxy)-1,1,1,3,3,3-hexafluoro-2-(trifluoromethyl)propane.

17. The method of claim 15 further comprises a third compound containing oxygen, argon, helium, xenon, krypton, or nitrogen.

18. The method of claim 15, wherein the first compound comprises more than or equal to about 1% by volume of the mixture and less than or equal to about 99% by volume of the mixture.

19. The method of claim 15, wherein the thin film of the integrated circuit material comprises silicon, silicon oxide, silicon dioxide, silicon carbide, silicon nitride, silicon carbonitride, silicon carbide oxycarbide, silicon oxynitride, silicon carbonitride oxycarbonitride, gallium nitride, aluminum gallium nitride, gallium arsenide, aluminum gallium arsenide, indium phosphide, indium aluminum arsenide, indium gallium arsenide, silicon germanium, silicon hydride bromide, zinc selenide, indium tin oxide, lead zirconate titanate, molybdenum, polycrystalline silicon, or combinations thereof.

20. The method of claim 15, wherein the thin film comprises silicon dioxide or silicon nitride, and the mixture has an etch selectivity of the thin film to the masking material layer greater than or equal to about 1.

21. The method of claim 15, wherein the masking material layer comprises a metal mask, a carbon hard mask, or a photoresist.

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