Method for forming nitrogen-containing carbon film and system for performing the same

Abstract

Disclosed are methods and systems for forming nitrogen-containing carbon films and structures formed using the methods or systems. An exemplary method includes providing a precursor having carbon-terminated carbon-nitrogen bonds. The method may also include providing a reactant to a reaction chamber.

Description

Technical Field

[0001] The present disclosure generally relates to methods suitable for use in fabricating electronic devices. More specifically, examples of the present disclosure relate to methods of forming nitrogen-containing carbon films, methods of forming structures including such films, and systems for performing the methods and / or forming the structures. Background Art

[0002] Nitrogen-containing carbon films can be used in a variety of applications during the manufacture of electronic devices. For example, nitrogen-containing carbon films can be used as optical films, etching hard mask films, gap fill films for trench patterns, etc. For some applications, relatively high etch resistance, chemical mechanical planarization (CMP) resistance, and / or thermal stability may be desired. The incorporation of nitrogen into nitrogen-containing carbon films can produce carbon-containing films that exhibit superior properties, such as improved etch resistance, improved CMP resistance, and / or thermal stability, compared to films that do not contain nitrogen-containing materials.

[0003] For some applications, nitrogen-containing carbon films may desirably be formed using a plasma process. Using a plasma process may allow for lower temperatures during film deposition and / or increased deposition rates of nitrogen-containing carbon films compared to thermal processes.

[0004] Conventional plasma-assisted processes for forming nitrogen-containing carbon films involve plasma bombarding the carbon film after film formation and adding N₂ and NH₃ to the gas phase during the film formation process. As verified by FTIR analysis, such techniques often result in C-NH₂ bond termination and dangling bonds. While such techniques work well for some applications, in other applications, it may be desirable to have or increase the amount of carbon-terminated carbon-nitrogen bonds, such as CNC and CN═C, in the nitrogen-containing carbon film. The inclusion of carbon-terminated carbon-nitrogen bonds can improve desirable chemical properties (e.g., etch resistance and CMP resistance) and physical properties (e.g., optical properties) of the nitrogen-containing carbon film.

[0005] Accordingly, there is a need for improved methods for forming nitrogen-containing carbon films, particularly methods for forming nitrogen-containing carbon films containing carbon-terminated carbon-nitrogen bonds such as CNC and CN═C.

[0006] Any discussion introduced in this disclosure, including discussions of problems and solutions set forth in this section, is introduced solely for the purpose of providing context for the disclosure and should not be construed as an admission that any or all of these discussions were known or otherwise constituted prior art at the time the invention was made. Summary of the Invention

[0007] Various embodiments of the present disclosure relate to methods for forming nitrogen-containing carbon films suitable for forming electronic devices. While the manner in which various embodiments of the present disclosure address shortcomings of existing methods and structures will be discussed in greater detail below, generally, exemplary embodiments of the present disclosure provide improved methods, including improved precursors, and techniques for forming nitrogen-containing carbon films.

[0008] According to various embodiments of the present disclosure, a method for forming a nitrogen-containing carbon film is provided. An exemplary method may include providing a precursor to a reaction chamber, and using the precursor to form a nitrogen-containing film on a surface of a substrate. Suitable precursors include compounds containing carbon-terminated carbon-nitrogen bonds, such as (CNC) a and / or (CN=C) a1 One or more compounds (1) represented by, wherein a and a1 are independently selected and are integers greater than or equal to 1, and (2) cyclic compounds having a ring structure comprising C, H, O and N. Exemplary cyclic compounds may comprise a cyclic skeleton comprising, for example, 5 to 7 atoms. The cyclic skeleton may comprise nitrogen. In some cases, the cyclic skeleton may be composed of one or more of C, O and N, such as consisting of C and N or consisting of O, C and N. The cyclic compound may be composed of C, H, O and N. The cyclic compound may comprise a cyclic skeleton and one or more atoms (e.g., hydrogen and / or oxygen), groups and / or side chains connected to the cyclic skeleton. At least one of the one or more side chains may include C w H x N y O z , wherein w, x, y and z are each independently selected and each is a natural number (including zero). The exemplary method may further include the step of providing reactants to the reaction chamber. Exemplary reactants include one or more of hydrogen, nitrogen, compounds containing hydrogen and nitrogen, and hydrocarbons.

[0009] According to still other exemplary embodiments of the present disclosure, a structure is formed at least in part by forming a nitrogen-containing carbon film as described herein.

[0010] According to still other exemplary embodiments of the present disclosure, a system for performing the methods described herein and / or for forming the structures described herein is provided.

[0011] These and other embodiments will become apparent to those skilled in the art from the following detailed description of certain embodiments taken in conjunction with the attached figures; the invention not being limited to any particular embodiment disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] A more complete understanding of exemplary embodiments of the present disclosure can be obtained by referring to the detailed description and claims when considered in conjunction with the following illustrative drawings.

[0013] Figure 1 A structure including a nitrogen-containing carbon film according to an exemplary embodiment of the present disclosure is illustrated.

[0014] Figure 2 and Figure 3 Molecules containing carbon-terminated carbon-nitrogen bonds are illustrated.

[0015] Figure 4 A system according to an exemplary embodiment of the present disclosure is illustrated.

[0016] It should be understood that the elements in the figures are illustrated for simplicity and clarity only and are not necessarily drawn to scale. For example, the dimensions of some elements in the figures may be exaggerated relative to other elements to help improve understanding of the embodiments of the present disclosure illustrated. DETAILED DESCRIPTION

[0017] Although certain embodiments and examples are disclosed below, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention and obvious modifications and equivalents thereof. Therefore, it is intended that the scope of the invention disclosed herein should not be limited by the specific disclosed embodiments described below.

[0018] The present disclosure generally relates to methods of forming nitrogen-containing carbon films, to methods of forming structures including such films, to film structures formed using the methods, and to systems for performing the methods and / or forming the film structures.

[0019] The exemplary methods described herein can be used to form nitrogen-containing carbon films having carbon-terminated carbon-nitrogen bonds or to form nitrogen-containing carbon films having an increased number of carbon-terminated carbon-nitrogen bonds, particularly CNC or CN═C. Such films can exhibit desirable properties, such as optical properties, increased resistance to (e.g., dry) etching, and / or increased CMP resistance. As described in more detail below, films containing CNC or CN═C can be obtained by using one or more precursors containing CNC or CN═C bonds.

[0020] In the present disclosure, depending on the context, "gas" can refer to a material that is a gas at normal temperature and pressure, a gasified solid and / or a gasified liquid, and can be composed of a single gas or a mixture of gases. Gases other than process gases, i.e., gases that are introduced without passing through a gas distribution component such as a showerhead, other gas distribution devices, etc., can be used to, for example, seal the reaction space, which includes sealing gases such as noble gases. In some cases, such as in the context of deposited materials, the term "precursor" can refer to a compound that participates in a chemical reaction to produce another compound, particularly a compound that constitutes the main skeleton of the membrane matrix or membrane, while the term "reactant" can refer to a compound that is not a precursor in some cases, which activates the precursor, modifies the precursor, or catalyzes the reaction of the precursor; when, for example, power (e.g., radio frequency (RF) or microwave power) is applied, the reactant can provide elements (such as O, H, N, C) to the membrane matrix and become part of the membrane matrix. In some cases, the terms precursor and reactant can be used interchangeably. The term "inert gas" refers to a gas that does not participate in the chemical reaction to an appreciable extent and / or a gas that excites the precursor (e.g., to promote polymerization of the precursor) when power (e.g., RF power) is applied, but unlike the reactants, may not become part of the film matrix to an appreciable extent.

[0021] As used herein, the term "substrate" may refer to any one or more underlying materials that may be used to form a device, circuit, or film, or on which a device, circuit, or film may be formed. A substrate may include a bulk material such as silicon (e.g., single crystal silicon), other Group IV materials such as germanium, or a compound semiconductor material such as a Group III-V or Group II-VI semiconductor, and may include one or more layers applied above or below the bulk material. Additionally, a substrate may include various features, such as gaps (e.g., recesses or vias), lines, or protrusions, such as lines with gaps formed therebetween, formed within or on at least a portion of a layer or bulk material of the substrate. As an example, one or more features may have a width of about 10 nm to about 100 nm, a depth or height of about 30 nm to about 1,000 nm, and / or an aspect ratio of about 3.0 to 100.0.

[0022] In some embodiments, "film" refers to a layer extending in a direction perpendicular to the thickness direction. In some embodiments, "layer" refers to a material having a certain thickness formed on a surface and can be a synonym for a film or non-film structure. A film or layer can be composed of a discrete single film or layer with certain properties, or it can be composed of multiple films or layers, and the boundaries between adjacent films or layers may or may not be clear and may or may not be created based on the physical, chemical and / or any other properties, formation process or sequence and / or function or purpose of adjacent films or layers. A layer or film can be continuous - or not continuous. In addition, a single film or layer can be formed using multiple deposition cycles.

[0023] As used herein, the term "nitrogen-containing carbon layer" or "nitrogen-containing carbon material" may refer to a layer whose chemical formula can be expressed as including carbon and nitrogen. The layer including the nitrogen-containing carbon material may include other elements, such as one or more of oxygen and hydrogen. The nitrogen-containing carbon layer desirably includes one or more of CNC and CN═C.

[0024] As used herein, the term "structure" may refer to a partially or fully fabricated device structure. For example, a structure may be or may include a substrate having one or more layers and / or features formed thereon.

[0025] As used herein, the term "cyclic deposition process" may refer to a vapor deposition process in which deposition cycles, typically multiple consecutive deposition cycles, are performed in a process chamber. Cyclic deposition processes may include cyclic chemical vapor deposition (CVD) and atomic layer deposition processes. A cyclic deposition process may include one or more cycles that include plasma activation of precursors, reactants, and / or inert gases.

[0026] In the present disclosure, in some embodiments and depending on the context, "continuously" may refer to no breaking of vacuum, no interruption in time, no intervening step of any material, immediately following, as the next step, or no discrete physical or chemical structures between two structures other than the two structures.

[0027] In the present disclosure, any two digits of a variable may constitute the working range of the variable, and any range indicated may include or exclude endpoints. In addition, any indicated variable values (whether or not they are indicated with "about") may refer to exact values or approximate values and include equivalent values, and in some embodiments may refer to average values, medians, representative values, majority values, etc. In addition, in the present disclosure, in some embodiments, the terms "comprising," "consisting of," and "having" may independently refer to "generally or broadly comprising," "comprising," "essentially consisting of," or "consisting of." In the present disclosure, in some embodiments, the meaning of any definition does not necessarily exclude common and customary meanings.

[0028] Figure 1 A structure 100 is illustrated, comprising a substrate 102 and a nitrogen-containing film 104 deposited on the substrate. According to examples of the present disclosure, the nitrogen-containing film 104 can be formed using methods described herein. Additionally or alternatively, the nitrogen-containing film 104 can include carbon-terminated carbon-nitrogen bonds. For example, all nitrogen-carbon bonds can be terminated with carbon-nitrogen bonds.

[0029] A method according to an exemplary embodiment of the present disclosure may include providing a precursor to a reaction chamber and forming a nitrogen-containing film on a surface of a substrate using the precursor. The method may also include providing a substrate to the reaction chamber and, in some embodiments, providing a reactant to the reaction chamber. The forming step may be thermally activated or plasma activated.

[0030] During the step of providing the precursors to the reaction chamber, one or more precursors are flowed into the reaction chamber of a gas phase reactor. According to examples of the present disclosure, the reaction chamber may form part of a cyclic deposition reactor such as an atomic layer deposition (ALD) (e.g., PEALD) reactor or a chemical vapor deposition (CVD) (e.g., PECVD) reactor. The various steps of the methods described herein may be performed in a single reaction chamber or in multiple reaction chambers, such as the reaction chambers of a cluster tool.

[0031] During the step of providing the substrate within the reaction chamber, before the step of providing the precursor to the reaction chamber, or during the step of providing the precursor to the reaction chamber, the substrate can be brought to a desired temperature and / or the reaction chamber can be brought to a desired pressure, such as a temperature and / or pressure suitable for subsequent steps. For example, the temperature within the reaction chamber (e.g., the substrate or substrate support) can be less than or equal to 400° C. or between about 550° C. and about 650° C. According to certain examples of the present disclosure, the substrate includes one or more features, such as a recess.

[0032] According to examples of the present disclosure, the precursor comprises one or more compounds in which one or more nitrogen atoms are bonded to a carbon atom, wherein the carbon atom is a terminal atom.

[0033] Figure 2 Molecules / compounds containing carbon-terminated carbon-nitrogen bonds are illustrated (N-methylmethylamine and trimethylamine). Although such compounds may work well for some applications, gases composed of such molecules may exhibit an unpleasant odor and therefore may need to be avoided in certain applications.

[0034] Figure 3 Illustrated are exemplary cyclic structures comprising cyclic backbones (e.g., ring portions of compounds / structures) according to examples of the present disclosure. The use of cyclic compounds comprising one or more carbon-terminated carbon-nitrogen bonds (e.g., within the backbone of the molecule) may be more desirable than linear or acyclic compounds comprising carbon-terminated carbon-nitrogen bonds because cyclic compounds having backbones comprising one or more carbon-terminated carbon-nitrogen bonds may not have the same unpleasant odor as linear compounds having one or more carbon-terminated carbon-nitrogen bonds. According to other examples of the present disclosure, the precursor does not comprise halogens such as fluorine (F), chlorine (Cl), bromine (Br), iodine (I), or astatine (At).

[0035] According to an embodiment of the present disclosure, the chemical formula of the precursor comprises one or more of the following: (1) (CNC) a and / or (CN=C) a1, wherein a and a1 are independently selected integers greater than or equal to 1, and (2) cyclic compounds, such as cyclic compounds having a ring structure containing C, H, O, and N. A may be, for example, in the range of about 3 to about 6. A1 may be in the range of about 3 to about 6.

[0036] According to examples of the present disclosure, the cyclic skeleton of the cyclic compound may include between 5 and 7 atoms. The cyclic skeleton may include one or more nitrogen atoms. The nitrogen atom in the cyclic skeleton may form a single bond or a double bond with the carbon in the cyclic skeleton. In addition to carbon and / or nitrogen, the cyclic skeleton may also include one or more oxygen atoms. In some cases, the cyclic skeleton may be composed of one or more of C, O and N--for example, composed of C and N or composed of C, N and O. According to further examples, the cyclic compound comprising the cyclic skeleton may be composed of one or more of C, H, O and N--for example, composed of C, H and N or composed of C, H, N and O.

[0037] Cyclic compounds may comprise one or more atoms, molecules, groups and / or side chains connected to the cyclic backbone. The atoms may include, for example, N, C, O and H. The molecules or groups may include, for example, methyl groups, ethyl groups, other hydrocarbon groups, hydroxyl groups, etc.

[0038] The side chain may include a chemical formula C w H x N y O z The molecule or group represented by wherein w, x, y and z are each independently selected and each is a natural number, and wherein the natural number may be 0. X may be in the range of 0 to 9 or 15, Y may be in the range of 0 to 3 or 6, and Z may be in the range of 0 to 3.

[0039] As a specific example, the precursor may be selected from one or more of 1,3,5-trimethylhexahydro-1,3,5-triazine, 1,3,5-triazine, 2,4,6-trimethyl-s-triazine, and 1-methyl-2-pyrrolidone.

[0040] The precursor may be a gas, liquid or solid at ambient temperature and pressure. In the case of a liquid or solid precursor, the precursor may be heated to a temperature sufficient to form a gaseous phase of the precursor.

[0041] As described above, methods according to the present disclosure may include providing a reactant to a reaction chamber. The reactant may be flowed to the reaction chamber during or overlapping in time with the step of providing a precursor to the reaction chamber. In some cases, the reactant may be pulsed into the reaction chamber. In some cases, the method for forming a nitrogen-containing carbon film includes a ring deposition method, wherein the steps of providing a precursor to the reaction and providing a reactant to the reaction chamber may be separated by a purge step. The purge step may include providing a vacuum and / or a purge gas to the reaction chamber.

[0042] According to embodiments of the present disclosure, the reactants include compounds comprising one or more of H, N, and C. In some cases, the compound may consist of one or more of H, N, and C. As examples, the reactants may include one or more of hydrogen, nitrogen, compounds comprising hydrogen and nitrogen (e.g., ammonia, hydrazine, etc.), and hydrocarbons (e.g., comprising only C and H).

[0043] According to other examples of the present disclosure, although the precursor may contain nitrogen, the amount of nitrogen in the nitrogen-containing carbon film may be manipulated by varying the (eg, volumetric) ratio of the flow rate of the precursor to the flow rate of the reactant.

[0044] One or more of the reactant and the precursor can be exposed to plasma to produce activated species. Plasma can be generated using direct plasma as discussed in more detail below and / or using remote plasma. In some cases, the reactant can be exposed to plasma to generate reactant activated species. In some cases, both the precursor and the reactant are exposed to plasma (e.g., simultaneously or during overlap). Activated species can be formed using continuous plasma or pulsed plasma. In some cases, an inert gas can be continuously flowed to the reaction chamber and can periodically form activated species by circulating the power used to form plasma.

[0045] The plasma may be formed using, for example, capacitively coupled plasma (CCP) and inductively coupled plasma (ICP), or surface plasma such as microwave plasma.

[0046] The power used to form or maintain the plasma (eg, the power applied to the electrodes) may be in the range of about 50 W to about 600 W. The frequency of the power may be in the range of about 10 kHz to about 100 MHz.

[0047] Figure 4 A reactor system 400 is illustrated according to an exemplary embodiment of the present disclosure. Reactor system 400 can be used to perform one or more steps or sub-steps as described herein, and / or to form one or more structures or portions thereof as described herein. For example, reactor system 400 can be used to generate a direct plasma for use in the methods disclosed herein.

[0048] Reactor system 400 includes a pair of parallel, mutually facing conductive plate electrodes 4 and 2 within interior 11 (reaction zone) of reaction chamber 3. Plasma can be ignited within reaction chamber 3 by applying HRF power (e.g., 13.56 MHz, 27 MHz microwave frequency, etc.) from power source 25, for example, to one electrode (e.g., electrode 4) and electrically grounding the other electrode (e.g., electrode 2). A temperature regulator can be provided in lower platform 2 (lower electrode) to maintain the temperature of substrate 1 placed thereon at a desired temperature. Electrode 4 can function as a gas distribution device, such as a shower plate. Reactant gas, dilution gas (if present), precursor gas, and / or the like can be introduced into reaction chamber 3 through shower plate 4 using one or more of gas lines 20, 21, and 22, respectively. Although illustrated as having three gas lines, reactor system 400 may include any suitable number of gas lines.

[0049] In the reaction chamber 3, an annular pipe 13 having an exhaust line 7 is provided, through which gas in the interior 11 of the reaction chamber 3 can be exhausted. Furthermore, the transfer chamber 5, disposed below the reaction chamber 3, is provided with a sealing gas line 24 for introducing sealing gas into the interior 11 of the reaction chamber 3 via the interior 16 (transfer zone) of the transfer chamber 5. A separation plate 14 for separating the reaction zone and the transfer zone is provided in the transfer chamber (a gate valve through which wafers are transferred into or from the transfer chamber is omitted in this figure). The transfer chamber is also provided with an exhaust line 6. In some embodiments, the deposition and processing steps are performed in the same reaction space, so that two or more (e.g., all) steps can be performed continuously without exposing the substrate to air or other oxygen-containing atmospheres.

[0050] In some embodiments, a continuous flow of inert gas or carrier gas to the reaction chamber 3 can be achieved using a flow-through system (FPS), wherein the carrier gas line is provided with a bypass line having a precursor storage tank (bottle), and switching between the main line and the bypass line is performed, wherein when only the carrier gas is intended to be fed to the reaction chamber, the bypass line is closed, and when both the carrier gas and the precursor gas are intended to be fed to the reaction chamber, the main line is closed, and the carrier gas flows through the bypass line and out of the bottle together with the precursor gas. In this way, the carrier gas can flow continuously into the reaction chamber and the precursor gas can be carried in a pulsed form by switching between the main line and the bypass line without substantially fluctuating the pressure of the reaction chamber.

[0051] The skilled artisan will recognize that the apparatus includes one or more controllers 26 that are programmed or otherwise configured to cause one or more of the method steps described herein to be performed. As the skilled artisan will appreciate, the one or more controllers may be in communication with various power supplies, heating systems, pumps, robotic devices, and reactor gas flow controllers or valves.

[0052] In some embodiments, a dual chamber reactor (for processing two portions or compartments of a wafer positioned close to each other) may be used, where reactant gases and noble gases may be supplied through shared lines while precursor gases are supplied through unshared lines.

[0053] The example embodiments of the present disclosure described above do not limit the scope of the present invention, as these embodiments are merely examples of embodiments of the present invention. Any equivalent embodiments are intended to be included within the scope of the present invention. In fact, various modifications of the present disclosure, such as alternative available combinations of the elements described, in addition to those shown and described herein, will be apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims.

Claims

1. A method for forming a nitrogen-containing carbon film by a cyclic deposition process, the method comprising the following steps: A precursor is provided to the reaction chamber, wherein the chemical formula of the precursor comprises: A cyclic compound having a ring structure comprising C, H, O, and N, wherein the cyclic compound includes one or more carbon-terminated carbon-nitrogen bonds, wherein the cyclic compound comprises a cyclic backbone consisting of one or more of C, O, and N; and A nitrogen-containing film is formed on the surface of a substrate using the precursor.

2. The method of claim 1, wherein the cyclic backbone comprises between 5 and 7 atoms. The method according to claim 1 , wherein the cyclic compound further comprises one or more side chains. The method according to claim 2 , wherein the cyclic compound further comprises one or more side chains.

5. The method of claim 3, wherein at least one of the one or more side chains has a chemical formula of CwHxNyOz, wherein w, x, y, and z are each independently selected and are each a natural number.

6. The method according to any one of claims 1 to 5, wherein the precursor is selected from one or more of 1,3,5-trimethylhexahydro-1,3,5-triazine, 1,3,5-triazine, 2,4,6-trimethyl-s-triazine and 1-methyl-2-pyrrolidone.

7. The method according to any one of claims 1 to 5, wherein the precursor is liquid or solid at normal temperature and pressure.

8. The method according to any one of claims 1 to 5, wherein the precursor is a gas at normal temperature and pressure.

9. The method according to any one of claims 1 to 5, further comprising the step of providing a reactant to the reaction chamber.

10. The method of claim 9, wherein the reactant comprises a compound comprising one or more of H, N, and C.

11. The method of claim 9, wherein the reactant comprises one or more of hydrogen, nitrogen, a compound comprising hydrogen and nitrogen, and a hydrocarbon.

12. The method of claim 9, further comprising the step of manipulating the amount of nitrogen in the nitrogen-containing carbon film by varying the ratio of the flow rate of the precursor to the flow rate of the reactant.

13. The method according to any one of claims 1 to 5, wherein the step of forming the nitrogen-containing carbon film is thermally activated.

14. The method according to any one of claims 1 to 5, wherein the step of forming the nitrogen-containing carbon film comprises a plasma process.

15. The method of claim 14, wherein the plasma process comprises direct plasma.

16. The method of claim 14, wherein the plasma process comprises using one or more of capacitively coupled plasma, inductively coupled plasma, and microwave plasma.

17. A method of forming a structure comprising the method according to any one of claims 1 to 16.

18. A system for performing the method according to any one of claims 1 to 17.

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