Methods and systems for forming boron-containing layers

Abstract

A method of forming a boron nitride layer on a surface of a substrate by a plasma-enhanced atomic layer deposition (PEALD) process. The method includes the steps of providing the substrate in a reaction chamber; and performing at least one deposition cycle. The deposition cycle includes providing a boron precursor into the reaction chamber, the boron precursor including a boron halide; and providing reactive species generated by a plasma generated from a reactant gas into the reaction chamber.

Description

Technical Field

[0001] This disclosure generally relates to methods and systems for depositing materials. More specifically, examples of this disclosure relate to methods and systems for forming boron nitride on a substrate surface. Background Technology

[0002] The use of boron nitride (BN) in the fabrication of electronic devices may be desirable for a variety of reasons. For example, boron nitride can be used to form layers with desired dielectric constant, etch resistance or chemical resistance, etch selectivity (e.g., wet or dry etch selectivity relative to silicon oxide and silicon nitride), mechanical properties (e.g., chemical mechanical polishing resistance compared to other dielectric materials), etc.

[0003] Methods for depositing boron nitride films may include plasma-enhanced chemical vapor deposition (PECVD) processes using cycloborazane as a precursor. Cycloborazane is a relatively expensive precursor. Furthermore, cycloborazane can polymerize during processing, which can lead to undesirable contamination and / or film properties. Other techniques have been used to deposit boron nitride, but such techniques may result in films with relatively poor barrier resistance and / or boron nitride films with undesirable high dielectric constants. Therefore, there is a strong need for improved methods for depositing boron nitride.

[0004] Any discussion set forth in this section (including discussions of problems and solutions) is included in this disclosure solely for the purpose of providing context for this disclosure. Such discussion should not be construed as an admission that any or all information was known at the time of making this invention or otherwise constitutes prior art. Summary of the Invention

[0005] This synopsis is provided to introduce some concepts in a simplified form. These concepts are further described in detail in the following detailed description of exemplary embodiments of this disclosure. This synopsis is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0006] According to examples of this disclosure, an exemplary method for forming boron nitride on the surface of a substrate is provided. The method may include the steps of: providing a substrate within a reaction chamber; and performing at least one deposition cycle. The deposition cycle includes providing a boron precursor, comprising boron halide, into the reaction chamber; and providing a reactive material generated by plasma produced by reactant gases into the reaction chamber.

[0007] In some embodiments, the boron nitride layer is essentially composed of boron and nitrogen.

[0008] In some embodiments, the boron nitride layer comprises amorphous boron nitride.

[0009] In some embodiments, the halogen in the boron halide is selected from a list including bromine, iodine, chlorine, and fluorine. In some embodiments, the boron precursor includes boron tribromide.

[0010] In some embodiments, the reactant gas comprises a mixture of nitrogen and hydrogen. In some embodiments, the reactant gas comprises ammonia. In some embodiments, the mixture comprises an N2 / H2 ratio of 2:1 to 20:1.

[0011] In some embodiments, the plasma is a direct plasma.

[0012] In some embodiments, a boron nitride layer is deposited on a non-planar substrate with a step coverage of more than 85%.

[0013] In some embodiments, the boron nitride layer has a dielectric constant of less than 3.5.

[0014] In some embodiments, the boron nitride layer has a density of less than 1E-8 A / cm. 2 @ 2 MV / cm leakage value.

[0015] In some embodiments, the ratio of the boron nitride layer to the wet etching rate of thermally oxidized silicon in dilute hydrofluoric acid (1:100) is less than 0.1.

[0016] In some embodiments, the plasma has a power between 100 W and 500 W.

[0017] In some embodiments, the plasma has an RF turn-on time between 4 seconds and 12 seconds.

[0018] In some embodiments, the deposition process is carried out at a temperature of 150-300°C.

[0019] In another aspect, a device structure is disclosed. This structure includes a layer of boron nitride formed according to the method of this disclosure.

[0020] In another aspect, a system for forming a boron nitride layer on the surface of a substrate is disclosed. The system includes a reaction chamber for housing the substrate; a boron precursor source fluidly connected to the reaction chamber via a first valve; a reaction gas source fluidly connected to the reaction chamber via a second valve; and a controller operatively connected to the first and second valves and configured and programmed to control: supplying the boron precursor in the reaction chamber; supplying the reaction gas; and depositing boron nitride on the substrate.

[0021] These and other embodiments will become apparent to those skilled in the art from the following detailed description of certain embodiments with reference to the accompanying drawings; the invention is not limited to any particular embodiment(s) disclosed. Attached Figure Description

[0022] Exemplary embodiments of this disclosure can be more fully understood by considering the following illustrative drawings, and by referring to the detailed embodiments and claims.

[0023] Figure 1 A method for forming boron nitride on the surface of a substrate according to at least one example of the present disclosure is shown.

[0024] Figure 2 A device structure including a boron nitride layer according to at least one embodiment of the present disclosure is shown.

[0025] Figure 3 A system for forming boron nitride on the surface of a substrate according to at least one embodiment of the present disclosure is shown.

[0026] It should be understood that the elements in the accompanying drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some elements in the drawings may be exaggerated relative to other elements to aid in understanding the embodiments shown in this disclosure. Detailed Implementation

[0027] Although certain embodiments and examples are disclosed below, those skilled in the art will understand that the invention extends beyond the specific disclosed embodiments and / or uses of the invention, as well as their obvious modifications and equivalents. Therefore, it is intended that the scope of the disclosed invention should not be limited to the specific disclosed embodiments described below.

[0028] Various embodiments of this disclosure relate to methods for forming boron nitride on the surface of a substrate, device structures and devices formed using such methods, and systems for performing the methods and / or forming the structures. While various embodiments of this disclosure address the shortcomings of existing methods and systems in more detail below, in general, the various embodiments of this disclosure provide improved methods for forming boron nitride that exhibits relatively high etch resistance and / or polishing resistance and / or relatively high thermal stability.

[0029] In this disclosure, "gas" can include materials that are gaseous at normal temperature and pressure (NTP), vaporized solids and / or vaporized liquids, and can consist of a single gas or a mixture of gases, depending on the context. Gases other than process gases, i.e., gases introduced without passing through gas distribution components, other gas distribution devices, etc., can be used, for example, to seal the reaction space, and can include sealing gases, such as rare gases.

[0030] The term "precursor" can refer to a compound that participates in a chemical reaction to produce another compound. The term "reactant" is used interchangeably with the term "precursor." The term "inert gas" can refer to a gas that does not participate in a chemical reaction and / or does not become part of the layer to a perceptible extent. Exemplary inert gases include helium and argon, and any combination thereof. In some cases, molecular nitrogen and / or hydrogen can be inert gases.

[0031] As used herein, the term "purge" can refer to the process of supplying an inert or substantially inert gas to a reactor chamber between two pulses of reacting gases. For example, a purge or purge gas can be supplied between pulses of two precursors to avoid or at least reduce gas-phase interactions between the two precursors. It should be understood that purging can be performed temporally, spatially, or both. For example, in the case of temporal purging, purging steps can be used, for instance, in a temporal sequence of supplying a first precursor to the reactor chamber, supplying a purge gas to the reactor chamber, and supplying a second precursor to the reactor chamber, wherein the substrate on which the deposited layer is deposited does not move. In the case of spatial purging, the purging step can be achieved by moving the substrate from (e.g., continuously) a first location supplying the first precursor via a purge gas curtain to (e.g., continuously) a second location supplying the second precursor.

[0032] As used herein, the term "substrate" can refer to any one or more underlying materials, including any one or more underlying materials that can be modified or on which devices, circuits, or films can be formed. A "substrate" can be continuous or discontinuous; rigid or flexible; solid or porous; and combinations thereof. A substrate can be in any form, such as powder, plate, or workpiece. Plate-type substrates can include wafers of various shapes and sizes. Substrates can be made of semiconductor materials, including, for example, silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride, and silicon carbide.

[0033] As an example, the powdered substrate may have applications for pharmaceutical manufacturing. Porous substrates may include polymers. Examples of workpieces may include medical devices (e.g., stents and syringes), jewelry, tooling, components for battery manufacturing (e.g., anodes, cathodes, or separators), or components for photovoltaic cells, etc.

[0034] The continuous substrate can extend beyond the boundaries of the processing chamber where the deposition process takes place. In some processes, the continuous substrate can move through the processing chamber, allowing the process to continue until the end of the substrate is reached. Continuous substrates can be supplied from a continuous substrate supply system to allow the continuous substrate to be manufactured and output in any suitable form.

[0035] Non-limiting examples of continuous substrates may include sheets, nonwoven films, rolls, foils, meshes, flexible materials, and bundles of continuous filaments or fibers (e.g., ceramic or polymer fibers). Continuous substrates may also include carriers or sheets on which non-continuous substrates are mounted.

[0036] In some embodiments of this disclosure, the substrate may include a patterned substrate comprising high aspect ratio features, such as, for example, trench structures, vertical gap features, horizontal gap features, and / or fin structures. For example, the substrate may include one or more substantially vertical gap features and / or one or more substantially horizontal gap features. The term "gap feature" can refer to an opening or cavity disposed between two protrusions or recesses extending vertically from the substrate surface and oppositely inclined sidewalls. Such a gap feature may be referred to as a "vertical gap feature." In some embodiments, the vertical gap feature may have an aspect ratio (height:width) greater than 2:1, or greater than 5:1, or greater than 10:1, or greater than 25:1, or greater than 50:1, or even greater than 100:1, where "greater than" as used in this example refers to a greater distance than the height of the gap feature.

[0037] As used herein, the terms “film” and / or “layer” can refer to any continuous or discontinuous structure and material, such as materials deposited by the methods disclosed herein. For example, films and / or layers can include two-dimensional materials, three-dimensional materials, nanoparticles, or even partially or entirely molecular layers or partially or entirely atomic layers or atomic and / or molecular clusters. Films or layers can include materials or layers with pinholes, which may be at least partially continuous.

[0038] As used herein, "structure" can be or includes a substrate as described herein. A structure may include one or more layers overlying a substrate, such as one or more layers formed according to the method of this disclosure.

[0039] The term "cyclic deposition process" or "cyclical deposition process" can refer to the sequential introduction of precursors (and / or reactants) into a reaction chamber to deposit a layer on a substrate, and includes processing techniques such as atomic layer deposition (ALD), cyclic chemical vapor deposition (cyclic CVD), and hybrid cyclic deposition processes that include ALD components and cyclic CVD components. The process may include purging steps between the introduction of precursors.

[0040] The term “atomic layer deposition” can refer to a vapor deposition process in which deposition cycles, typically multiple consecutive deposition cycles, are performed within a processing chamber. As used herein, the term atomic layer deposition is also intended to include processes specified by related terms such as chemical vapor deposition (CVD) when performed with alternating pulses of one or more precursor / reactive gases and one or more purge gases (e.g., inert support gases).

[0041] Typically, for ALD processes, during each cycle, a precursor is introduced into the reaction chamber and chemisorbed onto the deposition surface (e.g., a substrate surface that may include previously deposited material from a previous ALD cycle or other materials), forming approximately a monolayer or sub-monolayer of material that does not readily react with further precursors (i.e., a self-limiting reaction). Subsequently, in some cases, a reactant (e.g., another precursor or reactive gas) may be introduced into the processing chamber to convert the chemisorbed precursor into the desired material on the deposition surface. The reactant is capable of further reacting with the precursor. During one or more cycles, such as during each step of each cycle, a purging step may be utilized to remove any excess precursor from the processing chamber and / or any excess reactant and / or reaction byproducts from the reaction chamber.

[0042] As used herein, the term “plasma-enhanced atomic layer deposition” (PEALD) may refer to an ALD process in which one or more precursors, reactants and / or other gases are exposed to plasma to form an excitation material.

[0043] As used herein, “boron nitride” can be a material represented by a chemical formula comprising boron and nitrogen. In some embodiments, boron nitride may not include elements other than boron and nitrides in significant proportions. In some embodiments, boron nitride comprises BN. In some embodiments, boron nitride may consist substantially of BN. In some embodiments, boron nitride may consist of boron nitride. A layer composed of boron nitride may include acceptable amounts of impurities, such as hydrogen, carbon, iodine, bromine, and / or the like, which may originate from one or more precursors used to deposit the boron nitride.

[0044] As used herein, the term "comprising" means including certain features, but does not exclude the presence of other features, provided they do not render the statement impractical. In some embodiments, the term "comprising" includes "consisting of".

[0045] As used herein, the term "composed of" indicates that no other features exist in the apparatus / method / product besides the features following the wording. When the term "composed of" is used to refer to a compound, substance, or composition of substances, it indicates that the compound, substance, or composition of substances contains only the listed components. Similarly, when the term "substantially composed of" is used to refer to a compound, substance, or composition of substances, it indicates that the compound, substance, or composition of substances contains the listed components, but may also contain trace elements and / or impurities that do not substantially affect the properties of the compound, substance, or composition of substances. Nevertheless, in some embodiments, the compound, substance, or composition of substances may also include other components as trace elements or impurities in addition to the listed components.

[0046] In this specification, it will be understood that the terms "on" or "above" may be used to describe relative positional relationships. Another element, film, or layer may be directly on the mentioned layer, or another layer (intermediate layer) or element may be inserted between them, or a layer may be disposed on the mentioned layer but not completely cover the surface of the mentioned layer. Therefore, unless the term "directly" is used alone, the terms "on" or "above" will be interpreted as relative concepts. Similarly, it will be understood that the terms "below," "subject to," or "under" will be interpreted as relative concepts.

[0047] The term "substantially" applied to compositions, methods, or systems generally refers to a proportion of a value, property, characteristic, etc., or conversely, the absence of such proportion, i.e., at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 97%, at least about 98%, at least about 99%, at least about 99.5%, at least about 99.9% or more, or any proportion between about 70% and about 100%. In some embodiments, the term "substantially" means a proportion of about 90%, about 95%, about 97%, about 98%, about 99%, about 99.5%, or about 99.9%.

[0048] The term “substantially” when applied to compositions, methods, or systems generally means that the additional components do not substantially alter the properties and / or functions of the composition, method, or system.

[0049] Furthermore, in this disclosure, any two numbers of a variable may constitute a feasible range of the variable, and any indicated range may include or exclude endpoints. Additionally, any value of the indicated variable (whether or not it is indicated by “about”) may refer to an exact value or an approximate value and include equivalents, and may refer to an average, median, representative value, multi-value, etc. Furthermore, in this disclosure, the terms “comprising,” “consisting of,” and “having” may independently mean “generally or broadly comprising,” “including,” “substantially consisting of,” or “consisting of” in some embodiments. The meaning of any definition in this disclosure does not necessarily exclude the common and customary meaning in some embodiments.

[0050] Now turn to the attached image. Figure 1 A method 100 according to an exemplary embodiment of the present disclosure is shown. Method 100 can be used to form boron nitride on the surface of a substrate. In the example shown, method 100 includes the steps of providing a substrate (102) in a reaction chamber, providing a boron precursor (104) to the reaction chamber, and providing a reactant (106) to the reaction chamber.

[0051] During step 102, a substrate is provided within the reaction chamber. The reaction chamber used during step 102 may be or include the reaction chamber of a chemical vapor deposition reactor system configured to perform a deposition process. The deposition process may be a chemical vapor deposition process and / or a cyclic deposition process. The reaction chamber may be a standalone reaction chamber or part of a cluster tool. The reaction chamber may be a batch processing tool. In some embodiments, a flow reactor may be used. In some embodiments, a nozzle-type reactor may be used. In some embodiments, a space-separated reactor may be used. In some embodiments, a single-wafer reactor with high-volume manufacturing capabilities may be used. In other embodiments, a batch reactor comprising multiple substrates may be used. For embodiments in which a batch reactor is used, the number of substrates may range from 10 to 200, or 50 to 150, or even 100 to 130. The reactor may be configured as a thermal reactor—without plasma excitation equipment. Alternatively, the reactor may include direct and / or remote plasma equipment.

[0052] In some embodiments, the exposed surfaces of the substrate may be pretreated to provide reactive sites, if desired. In some embodiments, a separate pretreatment step is not required. In some embodiments, the substrate is pretreated, for example, by exposing the substrate surface to a pretreatment plasma to provide a desired surface termination state.

[0053] In some embodiments of this disclosure, the substrate disposed within the reaction chamber may be heated to a desired deposition temperature for subsequent deposition. For example, the substrate may be heated to temperatures less than about 600°C, less than about 500°C, less than about 450°C, less than about 400°C, less than about 350°C, less than about 300°C, less than about 250°C, or even less than about 200°C. In some embodiments of this disclosure, the substrate temperature during step 102 may be greater than room temperature, between about 300°C and about 600°C, or between about 350°C and about 550°C, or between about 200°C and about 400°C. Lower temperatures may be preferred for plasma-assisted processes, while higher temperatures may be desirable for thermal deposition processes. Temperatures during steps 104 and / or 106 may also be within these ranges.

[0054] In addition to controlling the substrate temperature, the pressure in the reaction chamber can also be adjusted to enable the deposition of the desired boron nitride. In some embodiments, the pressure can be controlled between about 0.5 Torr and about 50 Torr (e.g., for heat treatment) or between about 1 Torr and about 10 Torr (e.g., for plasma-enhanced processes). The pressure during steps 104 and / or 106 can also be within these ranges.

[0055] Once the substrate temperature has been set to the desired deposition temperature and the pressure in the reaction chamber has been adjusted as needed, method 100 can proceed to steps 104 and 106. When method 100 includes a CVD process, steps 104 and 106 can overlap. When method 100 includes a cyclic process, steps 104 and 106 can be performed sequentially, with an intermediate purge step between steps 104 and 106. During step 104, a boron precursor is supplied to the reaction chamber. In the case of cyclic deposition, the boron precursor can be pulsed into the reaction chamber. The term "pulse" can be understood to include supplying the precursor to the reaction chamber for a predetermined duration. Unless otherwise stated, the term "pulse" does not limit the length or duration of the pulse, and the pulse can be of any duration. In some embodiments, in addition to the boron precursor, a gas may be continuously supplied to the reaction chamber during the cyclic deposition process. In some embodiments, the gas may include a gas used to generate reactive substances used during a stage of the PEALD process, and may also be used as a purge gas to remove excess reactants, reactive substances, and reaction byproducts from the reaction chamber.

[0056] Following the initial surface treatment, a boron precursor pulse can be supplied to the substrate, if needed or desired. According to some embodiments, the boron precursor may be supplied to the reaction chamber along with a carrier gas stream. In some embodiments, the boron precursor may include a volatile boron substance that reacts with one or more surfaces of the substrate. The boron precursor pulse can self-saturate the substrate surface, preventing excess components of the boron precursor pulse from further reacting with the molecular layer formed by this process.

[0057] The boron precursor pulse is preferably supplied as a gaseous reactant. For the purposes of this disclosure, the boron precursor gas may be considered "volatile" if the material exhibits sufficient vapor pressure under process conditions to deliver the material at a sufficient concentration to the substrate surface to saturate the exposed surface.

[0058] In some embodiments of this disclosure, the gaseous boron precursor comprises boron and at least one halogen selected from iodine and bromine. In some cases, the boron precursor does not include fluorine and / or chlorine. According to some embodiments of this disclosure, the boron precursor consists of boron and one or more of iodine and bromine. For example, the boron precursor may be or include boron triiodide (BI3) and / or boron tribromide (BBr3).

[0059] In some embodiments of this disclosure, the boron precursor can be pulsed into the reaction chamber for a duration of about 0.05 seconds to about 5.0 seconds, or about 0.1 seconds to about 3 seconds, or even about 0.2 seconds to about 1.0 seconds. Furthermore, during the contact between the substrate and the boron precursor, the flow rate of the boron precursor can be less than 20 slm, or less than 10 slm, or less than 7 slm, or less than 5 slm, or even less than 3 slm. Additionally, during the contact between the substrate and the boron precursor, the flow rate of the boron precursor can be in the range of about 0.05 to 10 slm, about 0.1 to 7 slm, or about 0.1 to about 5 slm. In some embodiments, nitrogen is used as the carrier gas when the boron precursor is supplied to the reaction chamber.

[0060] In some embodiments, purging excess boron precursor can be achieved by stopping the flow of the gaseous boron precursor while continuing to allow the carrier gas, purge gas, or gas mixture to flow for a sufficient time to diffuse from the reaction chamber or to purge excess reactants and reactant byproducts (if any). In some embodiments, excess boron precursor can be purged by means of one or more inert gases (e.g., nitrogen, helium, or argon) that can flow throughout the cyclic deposition steps 104 and 106.

[0061] In some embodiments, the boron precursor may be purged from the reaction chamber for a period of about 0.1 seconds to about 10 seconds, or about 0.3 seconds to about 5 seconds, or even about 0.3 seconds to about 1 second. The provision and removal of the boron precursor may be considered as the first or “boron stage” of exemplary method 100.

[0062] After the excess boron precursor and any reaction byproducts in the reaction chamber have been purged, the cyclic deposition stage 108 of the exemplary PEALD process 100 can continue to a second stage via process block 106, which includes contacting the substrate with a reactive material generated by a plasma produced from a gas containing reactants.

[0063] In the second stage, a second reactant comprising a reactive substance generated by plasma is provided to the substrate. In some embodiments, the plasma based on the reactant is generated by a gas comprising the reactant. In some embodiments, the reactant may include a nitrogen-containing gas and another gas, such as nitrogen and hydrogen (N2 / H2). In some embodiments, the reactant may include ammonia. In some embodiments, the nitrogen-containing gas (e.g., N2) and another gas (e.g., H2) may be introduced into the reaction chamber at a nitrogen-to-hydrogen flow ratio greater than 1:1, or greater than 2:1, or greater than 2:1, or greater than 5:1, or greater than 10:1, or even equal to or greater than 20:1.

[0064] For example, nitrogen-based plasma can be generated by applying RF power of about 10 W to about 2000 W, or about 50 W to about 1000 W, or about 100 W to about 500 W. In some embodiments, the plasma can be generated in situ, while in other embodiments, the plasma can be generated remotely. In some embodiments, a nozzle reactor can be used, and the plasma can be generated between a base (with a substrate on top of it) and a nozzle plate.

[0065] In some embodiments, the reactive material generated from the plasma can contact the substrate for a period of time between about 0.1 seconds and about 20 seconds, or about 0.5 seconds and about 10 seconds, or even between about 0.5 seconds and about 5 seconds. In some embodiments, the reactive material generated from the plasma can contact the substrate for a period of time between about 2 seconds and 10 seconds.

[0066] After a sufficient period of time for the previously absorbed molecular layer to be fully saturated and reacted with the reactant-based plasma pulse, any excess reactants and reaction byproducts can be removed from the reaction chamber. Similar to the removal of the first reactant (i.e., the gaseous boron precursor), this step may include stopping the generation of reactive material and continuing the flow of an inert gas (such as a gas including nitrogen, helium, and, in some embodiments, argon). The inert gas flow can be sufficient to allow excess reactive material and volatile reaction byproducts to diffuse out of and be purged from the reaction chamber. For example, the purging process may utilize a time period between about 0.1 seconds and about 10 seconds, or about 0.1 seconds and about 4.0 seconds, or even between about 0.1 seconds and about 0.5 seconds. The provision and removal of nitrogen-based plasma together represent Figure 1 The second stage in the exemplary boron nitride PEALD process 100, namely the reactive material stage.

[0067] The method of alternately and sequentially contacting the substrate with a vapor boron precursor and with a reactive substance generated from a gas including a nitrogen precursor can constitute a unit deposition cycle. In some embodiments of this disclosure, the exemplary PEALD process 100 may include repeating a unit deposition cycle once or multiple times 108. For example, the cyclic deposition phase 108 of the exemplary PEALD process 100 may continue regardless of whether the desired thickness is not achieved, for example, if the thickness of the boron nitride film is insufficient for the desired device structure, then the PEALD process 100 may return to process block 104, and the processes of contacting the substrate with the boron precursor and contacting the substrate with the reactants (process block 106) may be repeated once or multiple times. For example, if the thickness of the boron nitride is less than the thickness required for a particular application, steps 104 and 106 may be repeated once or multiple times. In some embodiments, the method includes at least 1 cycle to a maximum of 100 cycles, or at least 2 cycles to a maximum of 80 cycles, or at least 3 cycles to a maximum of 70 cycles, or at least 4 cycles to a maximum of 60 cycles, or at least 5 cycles to a maximum of 50 cycles, or at least 10 cycles to a maximum of 40 cycles, or at least 20 cycles to a maximum of 30 cycles. In some embodiments, the method includes at most 100 cycles, or at most 90 cycles, or at most 80 cycles, or at most 70 cycles, or at most 60 cycles, or at most 50 cycles, or at most 40 cycles, or at most 30 cycles, or at most 20 cycles, or at most 10 cycles, or at most 5 cycles, or at most 4 cycles, or at most 3 cycles, or at most 2 cycles, or a single cycle.

[0068] Once the boron nitride film has been deposited to the desired thickness, the exemplary PEALD process 100 can be completed, and the boron nitride film can undergo further processes to form a semiconductor device structure.

[0069] Although PEALD cycles are generally referred to herein as beginning with the boron phase, it is contemplated in other embodiments that the cycle may begin with the reactive phase. Those skilled in the art will recognize that the first precursor phase typically reacts with the terminating state left by the last phase in the previous cycle. Therefore, while if the reactive phase is the first phase in a PEALD cycle, no reactant may have previously been absorbed onto the substrate surface or present in the reaction chamber, the reactive phase will effectively follow the boron phase in subsequent cycles. In some embodiments, one or more different PEALD cycles are provided in the deposition process.

[0070] In some embodiments, the growth rate of boron nitride film per deposition cycle can be greater than 0.01 nm / cycle, or greater than 0.02 nm / cycle, or greater than 0.03 nm / cycle. In some embodiments, at a deposition temperature greater than 250°C, the growth rate of boron nitride film per deposition cycle can be between about 0.01 and about 0.1 nm per cycle.

[0071] In some embodiments, boron nitride can be deposited to a thickness of about 1 nanometer to about 50 nanometers, or about 5 nanometers to about 30 nanometers, or about 5 nanometers to about 20 nanometers, or about 1 nanometer to 10 nanometers. These thicknesses can be achieved in feature sizes (widths) of less than about 100 nanometers, or less than about 50 nanometers, or less than about 30 nanometers, or less than about 20 nanometers, or even less than about 10 nanometers.

[0072] In some embodiments of this disclosure, boron nitride can be deposited on a three-dimensional structure, such as a non-planar substrate including a high aspect ratio feature. In some embodiments, in structures with an aspect ratio (height / width) greater than about 2, greater than about 5, greater than about 10, greater than about 25, greater than about 50, or even greater than about 100, the step coverage of the boron nitride film can be equal to or greater than about 50%, or greater than about 60%, or greater than about 70%, or greater than about 80%, or greater than about 90%, or greater than about 95%, or greater than about 98%, or greater than about 99%, or greater.

[0073] As described above, according to some examples of this disclosure, the deposition process can be a thermal deposition process. In these cases, the deposition process does not include the use of plasma to form an activating material for the deposition process. For example, the deposition process may not include the formation or use of plasma, may not include the formation or use of excited species, and / or may not include the formation or use of free radicals. In the case of a thermal cycling deposition process, the duration of the step of providing the precursor to the reaction chamber can be relatively long to allow the precursor to react with another precursor or its derivative. For example, the duration can be greater than or equal to 5 seconds, greater than or equal to 10 seconds, or between about 5 and 10 seconds.

[0074] In other cases, as mentioned herein, plasma can be used to excite one or more precursors and / or one or more inert gases.

[0075] Figure 2 The structure / part of a device 200 according to an additional example of this disclosure is shown. The device or structure 200 includes a substrate 202 and a boron nitride layer (or boron nitride layer) 204 formed on the substrate 202.

[0076] Substrate 202 may be or include any substrate material described herein. A boron nitride layer 204 may be formed according to the methods described herein. When layer 204 is formed using a cyclic deposition process, the concentrations of boron, nitrogen, and / or other components (e.g., carbon, hydrogen, etc.) in boron nitride layer 204 can vary from the bottom to the top of boron nitride layer 204, for example, by controlling the amount of boron precursors and / or (one or more) reactants and / or the corresponding pulse time or number of pulses during one or more deposition cycles. In some cases, boron nitride layer 204 may have a stoichiometric composition. Various properties of boron nitride layer 204 can be altered by changing the amount of boron, nitrogen, and / or other compounds in the layer or during the deposition cycle.

[0077] In some embodiments, boron nitride deposited according to the methods disclosed herein may have superior etch resistance compared to comparable boron nitride films deposited by existing processes. For example, in dilute hydrofluoric acid (1:100), the wet etch rate ratio (WERR) of the boron nitride film deposited by the methods of this disclosure relative to the wet etch rate of thermal silicon oxide may be less than 1.0, or less than 0.5, or less than 0.4, or less than 0.2, or less than 0.1, or between about 0.1 and about 1.0.

[0078] In some embodiments of this disclosure, wet etching of boron nitride deposited according to the methods disclosed herein in dilute hydrofluoric acid (1:100) at room temperature can be less than 1.5 nm / min, or less than 1.0 nm / min, or even less than 0.8 nm / min.

[0079] In some embodiments of this disclosure, boron nitride deposited according to the methods disclosed herein can have a thickness of less than 1E-6 A / cm at 10 nm. 2 @ Leakage value of 2MV / cm, for example, less than 1E-8 A / cm 2 @ 2MV / cm.

[0080] In some embodiments of this disclosure, boron nitride is essentially composed of boron and nitrogen. In some embodiments, the boron nitride film may include carbon-doped boron nitride.

[0081] In some cases, the boron nitride layer 204 is amorphous. In other cases, the boron nitride layer 204 is not polycrystalline.

[0082] The dielectric constant of the boron nitride layer 204 can be less than 4, less than 3.7, or less than 3.5. The dielectric constant can be greater than 2, greater than 2.5, or greater than 2.7.

[0083] Figure 3A system 300 according to another exemplary embodiment of the present disclosure is shown. The system 300 can be used to perform the methods described herein and / or form structural or device portions as described herein.

[0084] In the illustrated example, system 300 includes one or more reaction chambers 314, a boron precursor source 302 in fluid communication with reaction chamber 314 via a first valve 303, a nitrogen source 304 in fluid communication with reaction chamber 314 via a second valve 305, a third gas source (e.g., a carrier gas and / or purge gas source) 306 in fluid communication with reaction chamber 314 via a third valve 307; an exhaust source 316; and a controller 318. System 300 may optionally include a remote plasma source 320 to excite the gas from one or more sources 302-306.

[0085] The reaction chamber 314 may include any suitable reaction chamber, such as an ALD or CVD reaction chamber. The reaction chamber 314 may include a gas distribution system 322 (e.g., a nozzle) and a base 324 for holding the substrate. The gas distribution system 322 and the base 324 may be used to form a direct plasma within the reaction chamber 314.

[0086] Boron precursor source 302 may include a container and one or more boron precursors as described herein—alone or mixed with one or more carrier gases (e.g., inert gases). Nitrogen source 304 may include a container and one or more precursors as described herein (e.g., nitrogen precursors)—alone or mixed with one or more carrier gases. Third gas source 306 may include one or more inert gases and / or carrier gases as described herein. Although three gas sources 302-306 are shown, system 300 may include any suitable number of gas sources. Gas sources 302-306 may be connected to reaction chamber 314 via lines 308-312, each of which may include a flow controller, valve, heater, etc.

[0087] The exhaust source 316 may include one or more vacuum pumps.

[0088] Controller 318 may include electronic circuitry and software to selectively operate valves, manifolds, heaters, pumps, and other components included in system 300. Such circuitry and components may be operable to introduce precursors, reactants, and purge gases from respective sources 302-306. Controller 318 may control the timing of gas pulse sequences, the temperature of the substrate and / or reaction chamber, the pressure within the reaction chamber, and various other operations to provide appropriate operation of system 300. Controller 318 may include control software to electrically or pneumatically control valves to control the inflow and outflow of precursors, reactants, and purge gases from reaction chamber 314. Controller 318 may include modules, such as software or hardware components like FPGAs or ASICs, to perform certain tasks. Modules may advantageously be configured to reside on addressable storage media of the control system and to perform one or more processes. For example, controller 318 may be operatively connected to first valve 303 and second valve 305 and configured and programmed to control: supplying one or more boron precursors, including iodine and bromine, into the reaction chamber, and supplying a nitrogen precursor, including a substituted hydrazine compound, into the reaction chamber, thereby depositing boron nitride on the substrate.

[0089] Other configurations of system 300 are possible, including different numbers and types of precursor and reactant sources, as well as purge gas sources. Furthermore, it should be understood that numerous arrangements of valves, piping, precursor sources, and purge gas sources exist to achieve the objective of selectively supplying gases to reaction chamber 314. Additionally, for the sake of simplicity, many components have been omitted in the schematic diagram of the apparatus, and these components may include, for example, various valves, manifolds, purifiers, heaters, containers, vents, and / or bypasses.

[0090] During operation of the deposition system 300, a substrate, such as a semiconductor wafer (not shown), is transferred from, for example, a substrate handling system to a reaction chamber 314. Once the substrate(s) are transferred to the reaction chamber 314, one or more gases (e.g., precursors, reactants, carrier gases, and / or purge gases) from gas sources 302-306 are introduced into the reaction chamber 314 to deposit boron nitride.

[0091] The illustrations presented herein are not intended to be actual views of any particular material, structure, or device, but are merely idealized representations used to describe embodiments of this disclosure.

[0092] The specific embodiments shown and described are illustrative of the invention and its best mode, and are not intended to limit the scope of aspects and implementation in any way. In fact, for the sake of brevity, conventional manufacturing, connection, fabrication, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the figures are intended to represent exemplary functional relationships and / or physical connections between various elements. Many alternative or additional functional relationships or physical connections may exist in the actual system, and / or may not exist in some embodiments.

[0093] It should be understood that the configurations and / or methods described herein are exemplary in nature, and these specific embodiments or examples should not be considered limiting, as many variations are possible. The particular routines or methods described herein may represent one or more of any number of processing strategies. Therefore, the various actions shown may be performed in the order shown, in other orders, or in some cases omitted.

[0094] The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of various processes, systems and configurations, as well as other features, functions, actions and / or properties disclosed herein, and any and all their equivalents.

Claims

1. A method for forming a boron nitride layer on the surface of a substrate, the method comprising the following steps: A substrate is provided within the reaction chamber; as well as Perform at least one deposition cycle, wherein the deposition cycle includes: A boron precursor, comprising boron halide, is provided into the reaction chamber; and The reactive material generated from the plasma produced by the reactant gas is supplied to the reaction chamber.

2. The method according to claim 1, wherein, The boron nitride layer is essentially composed of boron and nitrogen.

3. The method according to claim 1 or 2, wherein, The boron nitride layer comprises amorphous boron nitride.

4. The method according to any one of the preceding claims, wherein, The halogens in the boron halides are selected from a list including bromine, iodine, chlorine, and fluorine.

5. The method according to any one of the preceding claims, wherein, The boron precursor includes boron tribromide.

6. The method according to any one of the preceding claims, wherein, The reactant gases include a mixture of nitrogen and hydrogen.

7. The method according to claim 5, wherein, The mixture comprises an N2 / H2 flow ratio of 2:1 to 20:

1.

8. The method according to any one of the preceding claims, wherein, The plasma is a direct plasma.

9. The method according to any one of the preceding claims, wherein, The boron nitride layer is deposited on a non-planar substrate with a step coverage of over 85%.

10. The method according to any one of the preceding claims, wherein, The boron nitride layer has a dielectric constant of less than 3.

5.

11. The method according to any one of the preceding claims, wherein, The boron nitride layer has a strength of less than 1E-8 A / cm. 2 @ 2 MV / cm leakage value.

12. The method according to any one of the preceding claims, wherein, The ratio of the wet etching rate of the boron nitride layer in dilute hydrofluoric acid (1:100) to that of thermally oxidized silicon is less than 0.

1.

13. The method according to any one of the preceding claims, wherein, The plasma is generated by applying RF power from 100 W to 500 W.

14. The method according to any one of the preceding claims, wherein, The plasma can contact the substrate for a period of 4 to 12 seconds.

15. The method according to any one of the preceding claims, wherein, The deposition process is carried out at a temperature of 150-300°C.

16. A device structure comprising a boron nitride layer formed according to the method of claim 1.

17. A system for forming a boron nitride layer on the surface of a substrate, the system comprising: The reaction chamber is used to contain the substrate; A boron precursor source, which is in fluid communication with the reaction chamber via a first valve; A reaction gas source, which is in fluid communication with the reaction chamber via a second valve; A controller, operably connected to the first valve and the second valve, and configured and programmed to control: Boron precursors are supplied in the reaction chamber; Supply of reactant gases; and The boron nitride is deposited on the substrate.

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