Structure including multiple carbon layers and methods for its formation and use

Abstract

Methods and systems for forming structures including multiple carbon layers are disclosed, as well as structures formed using such methods or systems. Exemplary methods include forming a first carbon layer and a second carbon layer, where the density and / or other properties of the first carbon layer are different from the corresponding properties of the second carbon layer.

Description

Technical Field

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

[0002] In the manufacture of devices such as semiconductor devices, it is generally desirable to fill gaps on a substrate surface, also known as trenches (e.g., grooves or regions between features), with an insulating or dielectric material. Some techniques for filling gaps include the deposition of carbon materials such as spin-on carbon (SOC) layers. For many applications, using carbon materials such as SOC has many desirable properties, such as filling ability, etch selectivity, ashing efficiency, etc.

[0003] While using carbon materials to fill gaps can work well for certain applications, filling gaps using traditional deposition techniques has several drawbacks, especially as the size of the gaps to be filled decreases. For example, it may be desirable to obtain a relatively flat carbon material surface for subsequent processes such as lithography, material etching, and / or material deposition. If the flatness and / or roughness of the carbon material surface is not at a suitable level, undesirable variations in critical dimension (CD) and / or line edge roughness (LER) may result in the subsequently formed resist patterns and features.

[0004] Chemical mechanical polishing (CMP) is typically used to make the surface of the carbon material flat and / or smooth, e.g., before a lithography step. However, in traditional carbon layer deposition processes, a carbon material with an undesirably low flatness may initially be formed, and the use of CMP may not be able to provide the desired flatness and / or smoothness.

[0005] In addition, the use of SOC may be relatively expensive because the SOC process uses additional process equipment such as coaters and ovens. Also, the SOC process typically includes additional process steps such as coating, baking, and curing. The use of such additional equipment and process steps may add unnecessary time and cost to the method of forming a structure for forming a device.

[0006] Therefore, improved methods for forming structures are desired, especially methods for filling gaps or trenches on a substrate surface with a carbon material, which are suitable for providing a relatively flat and smooth surface. Further improved structures and devices, and systems for forming such structures and devices, are also desired.

[0007] Any discussion included in this disclosure and set forth herein, including discussions of problems and solutions, is for the purpose of providing context for the disclosure only and should not be taken as an admission that any or all of the discussion was known or otherwise constitutes prior art at the time the invention was made. Summary of the Invention

[0008] Various embodiments of the present disclosure relate to methods of forming structures suitable for use in the formation of electronic devices, structures formed using such methods, and systems for performing such methods. Although the ways in which various embodiments of the present disclosure address the disadvantages of existing methods, structures, and systems are discussed in more detail below, generally, exemplary embodiments of the present disclosure provide improved methods for forming structures including two or more carbon layers having different properties. Compared to conventional methods, using two or more carbon layers in the formation of a structure, for example, for filling a trench, can improve the flatness of the trench fill material, which in turn can provide reduced critical dimension variation and reduced line edge roughness in the features formed using the methods described herein.

[0009] According to various embodiments of the present disclosure, methods of forming a structure are provided. Exemplary methods include: providing a substrate in a reaction chamber, forming a first carbon layer covering a surface, and forming a second carbon layer covering the first carbon layer. The substrate may include one or more trenches formed on the substrate surface. The first carbon layer and the second carbon layer may be used to fill one or more trenches (e.g., having an aspect ratio of about 3.0 to about 100.0) without void formation and to provide a relatively smooth surface for subsequent processes. According to examples of these embodiments, the density of the first carbon layer is greater than the density of the second carbon layer. For example, the density of the first carbon layer may be about 10% to about 50% greater than the density of the second carbon layer. Exemplary methods may additionally include a step of chemical mechanical polishing. The step of chemical mechanical polishing may be used to remove at least a portion of the second carbon layer. The step of chemical mechanical polishing may also be used to remove at least a portion of the first carbon layer. According to other aspects of these embodiments, the step of forming the first and / or second carbon layer includes a plasma process. Exemplary methods may include steps of etching the second carbon layer and the first carbon layer. In these cases, the etching may be non-selective such that the first carbon layer and the second carbon layer are etched at substantially the same rate (e.g., within a range of about 10%, 5%, 2%, or 1%). The step of etching the first carbon layer and the second carbon layer may include ion etching. According to yet another additional aspect of these embodiments, the method may include forming a third layer covering the second carbon layer. The third layer may include a third carbon layer. The composition of the third layer may be the same as the composition of the second carbon layer.

[0010] According to other exemplary embodiments of the present disclosure, a structure is formed at least in part according to the methods described herein. The structure may include a first carbon layer and a second carbon layer.

[0011] According to yet another exemplary embodiment of the present disclosure, a system for performing a method and / or for forming a film structure as described herein is provided. The exemplary embodiment may include one or more reaction chambers, a carbon precursor source, an inert gas source, a plasma power source, an exhaust source, and a controller. The controller may be configured to control the gas flow of the carbon precursor into at least one of the one or more reaction chambers to form a first carbon layer and a second carbon layer covering the first carbon layer, wherein the density of the first carbon layer is greater than the density of the second carbon layer.

[0012] 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 disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] A more complete understanding of the exemplary embodiments of the present disclosure can be obtained by reference to the detailed description and the claims when considered in conjunction with the following illustrative drawings.

[0014] Figure 1 A method according to an exemplary embodiment of the present disclosure is shown.

[0015] Figure 2 A method according to an exemplary embodiment of the present disclosure is shown.

[0016] Figures 3 - 6 A structure according to an exemplary embodiment of the present disclosure is shown.

[0017] Figure 7 An additional structure according to an exemplary embodiment of the present disclosure compared to other structures is shown.

[0018] Figure 8 、 Figure 9 and Figure 11 A timing diagram according to an exemplary embodiment of the present disclosure is shown.

[0019] Figure 10 A system according to an exemplary embodiment of the present disclosure is shown.

[0020] It will be appreciated that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to assist in improving the understanding of the illustrated embodiments of the present disclosure. DETAILED DESCRIPTION

[0021] Although certain embodiments and examples are disclosed below, those skilled in the art will understand that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention and their obvious modifications and equivalents. Accordingly, it should be recognized that the scope of the disclosed invention should not be limited by the specific disclosed embodiments described below.

[0022] The present disclosure generally relates to methods of forming structures, structures formed using such methods, and systems for performing such methods and / or forming structures. As an example, the methods described herein can be used to fill grooves or gaps (e.g., trenches or vias or the spacing between features such as lines or protrusions) on a substrate surface with a carbon material.

[0023] Exemplary methods include forming two or more carbon layers having different properties (e.g., hardness, modulus, polish rate, and / or density). Using multiple carbon layers, where at least two layers exhibit different properties, can provide desired groove filling performance while also providing desired polishing (e.g., chemical mechanical polishing) and / or etching performance of the carbon material. Additionally, structures formed using two or more carbon layers can (e.g., after polishing and / or etching) exhibit a relatively flat and smooth surface that is suitable for subsequent processes such as photoresist patterning, etching, etc. The relatively flat and smooth surface of the structure can result in reduced critical dimension (CD) variation and / or reduced line edge roughness (LER) in the patterning of a patterned resist layer and / or features formed on the surface of the structure.

[0024] A carbon layer with a relatively low density may be desirable for polishing (e.g., CMP). The density of a carbon layer can generally be related to the modulus and polish rate of the carbon layer. A high polish rate generally allows for higher device manufacturing throughput. On the other hand, a carbon layer with a relatively low density may not be suitable for use as a mask in subsequent etching processes because a carbon layer with a relatively low density may be unstable during etching, resulting in features with relatively large CD and / or LER variations. Using two carbon layers can provide a desired polish rate while also providing a carbon layer with a relatively high density for pattern transfer.

[0025] In the present disclosure, "gas" can refer to a material that is a gas, vaporized solid, and / or vaporized liquid at normal temperature and pressure, and can consist of a single gas or a gas mixture, depending on the context. Gases other than process gases (i.e., gases that are not introduced through a gas distribution component such as a showerhead, other gas distribution devices, etc.) can be used, for example, to seal a reaction space, which includes a sealing gas such as a noble gas. In some cases, such as in the context of the deposition of materials, the term "precursor" can refer to a compound that participates in a chemical reaction to produce another compound, and particularly refers to a compound that constitutes the main framework of a film array or film, while the term "reactant" can refer to a compound that activates, modifies, or catalyzes the reaction of a precursor (in some cases different from the precursor); a reactant can provide elements (such as O, H, N, C) to the film array and become part of the film array when, for example, power is applied (e.g., radio frequency (RF) power). In some cases, the terms "precursor" and "reactant" can be used interchangeably. The term "inert gas" refers to a gas that largely does not participate in chemical reactions and / or a gas that stimulates a precursor (e.g., aids in the polymerization of a precursor) when, for example, power is applied (e.g., RF power), but unlike a reactant, an inert gas is highly unlikely to become part of the film array.

[0026] As used herein, the term "substrate" can refer to any underlying material or a material on which a device, circuit, or film can be formed or can be used to form. The substrate can include bulk materials such as silicon (e.g., single-crystalline silicon), other Group IV materials (such as germanium), or compound semiconductor materials (such as III-V or II-VI semiconductors), and can include one or more layers on or under the bulk material. In addition, the substrate can include various features such as gaps, lines, or protrusions, such as lines with gaps formed between the features, and the like formed on, within, or on at least a portion of the layers or bulk material of the substrate. As an example, one or more features (e.g., grooves, lines, or protrusions) can have a width of about 10 nm to about 30 nm, a depth or height of about 30 nm to about 1000 nm, and / or an aspect ratio of about 3.0 to 100.0.

[0027] In some embodiments, a "film" refers to a layer that extends in a direction perpendicular to the thickness direction. In some embodiments, a "layer" refers to a material having a certain thickness formed on a surface, and can be a synonym of a "film" or a non-film structure. A film or layer can be composed of an independent single film or layer or multiple films or layers having certain properties, and the boundary between adjacent films or layers may be clear or unclear and may be established or not established based on physical, chemical, and / or any other properties, formation processes or sequences, and / or the functions and purposes of the 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 and / or multiple deposition and processing cycles.

[0028] As used herein, the term "carbon layer" can refer to a layer whose chemical formula can be represented as including carbon. A layer including a carbon material can include other elements, such as one or more of nitrogen and hydrogen. Similarly, the term "carbon material" can refer to a material whose chemical formula can be represented as including carbon. A carbon material can include one or more carbon layers.

[0029] As used herein, the term "structure" can refer to a partially or fully fabricated device structure. By way of example, a structure can be a substrate or a substrate including one or more layers and / or features formed thereon.

[0030] As used herein, the term "cyclic deposition process" can refer to a vapor deposition process in which deposition cycles (usually multiple consecutive deposition cycles) are performed in a processing chamber. Cyclic deposition processes can include cyclic chemical vapor deposition (CVD) and atomic layer deposition processes. A cyclic deposition process can include one or more cycles that include plasma activation (e.g., pulsing) of a precursor, reactant, and / or inert gas and / or pulsing of a precursor into the reaction chamber.

[0031] In the present disclosure, "continuously" can refer to, in some embodiments and depending on the context, without breaking vacuum, without interrupting the timeline, without material intervention steps, without changing processing conditions, immediately following it as the next step, or without intervening between two structures an independent physical or chemical structure other than the two structures.

[0032] The fluidity (e.g., initial fluidity) can be determined as follows:

[0033] Table 1

[0034] Bottom / Top Ratio (B / T) Flowability 0 < B / T < 1 None 1 ≤ B / T < 1.5 Poor 1.5 ≤ B / T < 2.5 Good 2.5 ≤ B / T < 3.5 Very Good 3.5 ≤ B / T Excellent

[0035] Herein, B / T refers to the ratio of the film thickness deposited at the bottom of the groove and the film thickness deposited on the top surface forming the groove before filling the groove. Generally, wide grooves having an aspect ratio of about 1 or less are used to evaluate fluidity because generally, the larger the aspect ratio of the groove, the larger the B / T ratio becomes. The B / T ratio generally becomes larger when the aspect ratio of the groove is large. As used herein, a "flowable" film or material exhibits good or better fluidity.

[0036] As elaborated in more detail below, the fluidity of the film can be obtained when a volatile hydrocarbon precursor, e.g., is polymerized and deposited on the substrate surface by plasma, wherein the gaseous precursor is activated or split by the energy provided by plasma gas discharge to initiate polymerization. The synthesized polymeric material can exhibit temporary flowable characteristics. When the deposition step is completed and / or after a short period of time (e.g., about 3.0 seconds), the film may no longer be flowable but become solidified, so that, therefore, a separate curing process may not be employed.

[0037] In the present disclosure, any two numbers of a variable can constitute a feasible range of the variable, and any range represented can include or exclude endpoints. Additionally, any value of a variable represented (whether or not denoted by "about") can refer to an exact value or an approximate value and include equivalent values, and in some embodiments can refer to an average, median, representative number, mode, etc. Further, in the present disclosure, the terms "including", "constituted by", and "having" can independently refer to "generally or broadly including", "comprising", "substantially consisting of", or "consisting of" in some embodiments. In the present disclosure, the meaning of any definition in some embodiments does not necessarily exclude the ordinary meaning or customary meaning.

[0038] Now turning to the drawings, Figure 1 An exemplary method 100 according to an example of the present disclosure is shown. Method 100 includes the following steps: providing a substrate in a reaction chamber (step 102), forming a first carbon layer (step 104), and forming a second carbon layer (step 106). As further shown, method 100 may optionally include one or more of etching one or more of the second carbon layer and the first carbon layer (step 108) and / or polishing (e.g., chemical mechanical polishing) (step 110).

[0039] In step 102 of providing a substrate in a reaction chamber, the substrate is provided into the reaction chamber of a gas-phase reactor. According to an example of the present disclosure, the reaction chamber can form part of a cyclic deposition reactor, such as an atomic layer deposition (ALD) (e.g., plasma-enhanced ALD (PEALD)) reaction chamber or a chemical vapor deposition (CVD) (e.g., plasma-enhanced CVD (PECVD)) reactor. The various steps of the methods described herein can be performed in a single reaction chamber or can be performed in multiple reaction chambers (such as the reaction chambers of a cluster tool).

[0040] In step 102, the substrate can be provided at a desired temperature and / or the reaction chamber can be provided at a desired pressure, such as a temperature and / or pressure suitable for subsequent steps. In an example, the temperature in the reaction chamber (e.g., the temperature of the substrate or the substrate support) can be less than or equal to 100 °C. The pressure in the reaction chamber can be from about 200 Pa to about 1250 Pa. According to a specific example of the present disclosure, the substrate includes one or more features. In some cases, the features can extend from the surface of the substrate. In these cases, grooves can be formed between the features.

[0041] Referring to Figure 1 and Figure 3 , in step 104, a first carbon layer 304 is formed to cover the surface of the substrate 302 to form a structure 300. As shown, the substrate 302 can include features 306 and 308 and a groove 310 formed therebetween. The height of the first carbon layer 304 relative to the substrate surface can be greater than that of the features 306, 308 relative to the surface substrate.

[0042] Figure 2 An exemplary method 200 of forming a carbon layer (e.g., the first, second, or third carbon as described herein) is shown. Method 200 can be used for step 104 and / or step 106 of method 100.

[0043] Method 200 includes the following steps: providing a carbon precursor to the reaction chamber (step 202), providing a plasma in the reaction chamber (step 204), and a processing step (206). Additionally, method 200 can include providing one or more inert gases to the reaction chamber and / or providing one or more reactive gases to the reaction chamber.

[0044] One or more inert gases may include, for example, one or more of argon, helium, and nitrogen in any combination. In a specific example, the inert gas is helium or includes helium. In this step, the flow rate of the inert gas into the reaction chamber may be from about 500 sccm to about 8000 sccm. The inert gas can be used to: ignite a plasma in the reaction chamber or assist in the ignition of the plasma, remove reactants and / or by-products from the reaction chamber, and / or be used as a carrier gas to assist in delivering the precursor to the reaction chamber. The power used to ignite and sustain the plasma may be in the range from about 50 W to about 800 W. The frequency of the power may be in the range from about 2.0 MHz to about 27.12 MHz.

[0045] In step 202, a carbon precursor for forming a carbon layer is introduced into the reaction chamber. Exemplary precursors include compounds represented by the formula CxHyNz, where x is a natural number greater than or equal to 2, y is a natural number, and z is zero or a natural number. For example, x may be in the range from about 2 to about 15, y may be in the range from about 4 to about 30, and z may be in the range from about 0 to about 10. The precursor may include a chain or cyclic molecule having two or more carbon atoms and one or more hydrogen atoms, such as the molecule represented by the above formula. In a specific example, the precursor may be or include one or more cyclic (e.g., aromatic) structures and / or a compound having at least one double bond, and in some cases, including two or more or three or more double bonds. In a specific example, the carbon precursor may be or include 1,3,5-trimethylbenzene or 2,4,6-trimethylpyridine.

[0046] The flow rate of the carbon precursor from the carbon precursor source to the reaction chamber may vary according to other process conditions. In an example, the flow rate may be from about 100 sccm to about 3000 sccm. Similarly, the duration of each step of providing the carbon precursor to the reaction chamber may vary according to various considerations. In an example, the duration may be in the range from about 1.0 second to about 35.0 seconds.

[0047] Continuing to refer to Figure 2 , a plasma is formed in the reaction chamber to form an initial viscous carbon material on the substrate surface. Once the carbon precursor is provided to the reaction chamber and a plasma is formed, the carbon precursor is converted into an initial viscous (flowable) carbon material using excited species. The initial viscous carbon material may become a carbon layer, for example, by further reacting with the excited species. The carbon layer may be solid or substantially solid.

[0048] In step 206, the carbon layer may be treated with an active substance to form, for example, an increased density and / or hardness of the carbon layer. Step 206 may include forming the substance from an inert gas (such as the inert gas provided in the step of providing the inert gas to the reaction chamber). The power used to form the plasma may be in the range of from about 50 W to about 800 W. The frequency of the power may be in the range of from about 2.0 MHz to about 27.12 MHz.

[0049] In step 206, the active species may be formed by using a plasma (eg, a radio frequency and / or microwave plasma). Direct plasma and / or remote plasma may be used to form the active species.

[0050] In some cases, an inert gas may be continuously flowed into the reaction chamber, and the reactive species may be periodically formed by cycling the power used to form the plasma. The species formation for the process steps may be formed in the same reaction chamber used for one or more or other steps, or may be a separate reaction chamber, such as another reaction chamber of the same cluster tool.

[0051] The temperature within the reaction chamber in steps 202-206 may be less than or equal to 100° C. The pressure within the reaction chamber during formation of the species for treatment may be from about 200 Pa to about 1250 Pa.

[0052] The steps of the various methods described herein may overlap and do not need to be performed in the order described above. For example, the order of step 204 of step 202 may be reversed. In addition, in some cases, various steps or parts thereof may be repeated once or more times before the method enters the next step. For example, step 202 and step 204 may be repeated once or more times (e.g., about 01 to about 20 times (loop 208)) before the method 200 enters step 206. Similarly, steps 202-206 (with or without repetition loop 208) may be repeated several times before entering the next step (e.g., the next step of method 100).

[0053] Figure 8 , Figure 9 and Figure 11 An exemplary timing diagram suitable for use with method 200 is shown. Figure 8 , Figure 9 and Figure 11An inert gas, a carbon precursor, and a plasma power pulse are shown, where a pulse cycle of gas and / or plasma power is provided to the reactor system. The width of the pulse does not necessarily indicate the amount of time associated with each pulse; the pulses shown can show the relative start times of various pulses. Similarly, the height of the pulses shown does not necessarily indicate a specific amplitude or value, but can show relatively high and low (e.g., on and off) values. These examples are illustrative only and are not intended to limit the scope of the present disclosure or claims.

[0054] Figure 8 A sequence 800 suitable for use as method 200 is shown. The sequence 800 can include one or more carbon material deposition steps 802(n) and one or more processing steps 804. According to examples of these embodiments, n can range from approximately about 1 to approximately about 50, and the combination of n deposition cycles and one or more processing steps can be repeated N times, where N ranges from approximately about 1 to approximately about 50.

[0055] As shown, during one or more of the carbon material deposition steps 802 and / or one or more of the processing steps 804, the sequence 800 can include continuously supplying an inert gas to the reaction chamber. In the example shown, a pulse cycle 806 of inert gas is provided to the reaction chamber, which pulse cycle 806 begins before the first deposition step 802 and can end after the last processing step 804. The pulse cycle can be referred to simply as a pulse.

[0056] After the start of the pulse cycle 806, a pulse cycle 808 of carbon precursor is provided to the reaction chamber. The pulse cycle 808 can range from, for example, approximately about 1.0 second to approximately about 35.0 seconds. Each pulse cycle 808 can be the same or vary in time.

[0057] After the flow of carbon precursor to the reaction chamber begins, a pulse cycle 810 of power for forming a plasma is provided. Thus, in the example shown, both the inert gas and the carbon precursor are provided to the reaction chamber when the plasma has been ignited / formed. The pulse cycle 810 can range from, for example, about 1.0 second to about 30.0 seconds. Each pulse cycle 810 can be the same or vary in time.

[0058] As shown in this example, the pulse cycle 808 can end before the cycle 810. However, in some cases, the pulses 808 and 810 can overlap in time. Once the flow of carbon precursor to the reaction chamber and the plasma power stop, the reaction chamber can be cleaned for a cleaning cycle. The cleaning cycle can range from, for example, about 5.0 seconds to about 30.0 seconds. Each cleaning cycle 810 can be the same or vary in time.

[0059] The power during pulse 810 (e.g., applied to the electrode) can be in the range from about 100 W to about 800 W. The frequency of the power can be in the range from about 2.0 MHz to about 27.12 MHz.

[0060] After pulse period 810, the plasma power can be increased to the desired level for treating the carbon material for one pulse period 812 using the active substance. The power level and pressure in the reaction chamber can be as described above. Pulse period 812 can be in the range from, for example, about 1.0 second to about 30.0 seconds. Each pulse period 812 can be the same or vary in time. The power, pulse time, and / or number of pulses in step 804 can vary according to the desired carbon layer properties. For example, in step 804, one or more of the power, pulse time, and / or number of pulses for the first carbon layer, in any combination, can be relatively greater than those for the second carbon layer.

[0061] After the step of treating the carbon material for one or more pulse periods 812 using the active substance, the reaction chamber can be cleaned for a second cleaning cycle. The second cleaning cycle can be in the range from, for example, about 10.0 seconds to about 70.0 seconds. Each second cleaning cycle can be the same or vary in time.

[0062] Figure 9 Another sequence 900 suitable for use as method 200 is shown. Similar to sequence 800, sequence 900 can include one or more carbon material deposition steps 902(n) and one or more treatment steps 904. According to an example of these embodiments, n can be in the range from about 1 to about 50, and the combination of n deposition cycles and one or more treatment steps can be repeated N times, where N is in the range from about 1 to about 50.

[0063] During one or more of the carbon material deposition steps 902 and / or one or more of the treatment steps 904, sequence 900 can include continuously supplying an inert gas to the reaction chamber. In the example shown, a pulse period 906 of inert gas is provided to the reaction chamber, which starts before the first deposition step 902 and can end after the last treatment step 904.

[0064] After the start of pulse period 906, power for forming a plasma is provided for a pulse period 910. As shown, pulse period 906 can start before the first pulse 908 of introducing a carbon precursor into the reaction chamber and can continue until the final processing step 904. The power provided during pulse 910 can start before the first pulse 908 and can continue until the final processing step 904. The power level and frequency of plasma pulse 910 can be as described above in connection with pulse 810. Pulse 908 can be the same as or similar to the above-described pulse 808.

[0065] After each pulse 908, the reaction chamber can be cleaned. The cleaning time can be as described above in connection with the first cleaning time. After the step of treating the carbon material with an active substance, the reaction chamber can be cleaned for a second cleaning cycle. The second cleaning cycle can be in the range from, for example, about 10.0 seconds to about 70.0 seconds. Each second cleaning cycle can be the same or vary in time.

[0066] In some cases, the power and / or frequency for forming the plasma in sequence 900 can be constant, and the amount of time for the processing step can be used to form carbon layers with different properties (e.g., density, hardness, etc.).

[0067] Figure 11 Another sequence 1100 suitable for use as method 200 is shown. Similar to sequence 800 and sequence 900, sequence 1100 can include one or more carbon material deposition steps 1102(n) and one or more processing steps 1104. According to an example of these embodiments, n can be in the range from about 1 to about 50, and the combination of n deposition cycles and one or more processing steps can be repeated N times, where N is in the range from about 1 to about 50.

[0068] During one or more of the carbon material deposition steps 1102 and / or one or more of the processing steps 1104, sequence 1100 can include continuously supplying an inert gas to the reaction chamber. In the example shown, a pulse period 1106 of inert gas is provided to the reaction chamber, and this pulse period 1106 starts before the first deposition step 1102 and can end after the final processing step 1104.

[0069] After the start of pulse period 1106, a pulse period 1108 of carbon precursor is provided to the reaction chamber. The pulse period 1108 can be in the range from, for example, about 1.0 seconds to about 35.0 seconds. Each pulse period 1108 can be the same or vary in time.

[0070] After the flow of the carbon precursor into the reaction chamber begins, power for forming a plasma is provided for a pulse period 1110. Thus, when the plasma has been ignited / formed, both the inert gas and the carbon precursor are provided to the reaction chamber. The pulse period 1110 can range from, for example, about 1.0 second to about 30.0 seconds. Each pulse period 1110 can be the same or vary in time. The plasma power level and frequency, as well as the flow rate of the precursor, can be as described above.

[0071] As shown in this example, the pulse period 1108 can end before the period 1110. Once the flow of the carbon precursor into the reaction chamber and the plasma power stop, the reaction chamber can be cleaned for a cleaning period. The cleaning period can range from, for example, about 5.0 seconds to about 30.0 seconds. Each cleaning period can be the same or vary in time.

[0072] After the step of treating the carbon material for one or more pulse periods 1104 with the active substance, the reaction chamber can be cleaned for a second cleaning period. The second cleaning period can range from, for example, about 1.0 second to about 70.0 seconds. Each second cleaning period can be the same or vary in time.

[0073] Referring to Figure 1 and Figure 4 , after the first carbon layer 304 is formed (e.g., using method 200 (e.g., in accordance with sequence 800, sequence 900, or sequence 1100)), method 100 proceeds to step 106 of forming a second carbon layer 402 to form structure 400. The second carbon layer 402 can be formed (e.g., directly) over the first carbon layer 304.

[0074] As described above, method 200 (e.g., sequence 800, sequence 900, or sequence 1100) can be used to form the second carbon layer 402. According to an example of the present disclosure, the processing steps of method 200 for forming the second carbon layer 402 result in the second carbon layer 402 having a lower density and / or exhibiting a lower hardness relative to the first carbon layer 304. In an example, the density of the first carbon layer can be about 10% to about 50% greater than the density of the second carbon layer. The control of the hardness of the first carbon layer and / or the second carbon layer can be achieved by, for example, selecting the number (n) of deposition steps before one or more processing steps and / or the time, power, or electrode spacing in the respective deposition and processing steps.

[0075] Once the second carbon layer 402 is formed to the desired thickness, structure 400 can be exposed in one or more of step 108 and / or step 110.

[0076] Step 108 may include etching the second carbon layer 402 and / or the first carbon layer 304. According to an example of the present disclosure, step 108 includes non-selectively etching the second carbon layer 402 and the first carbon layer 304. As used herein, non-selectively etching may mean that the etching rate of the second carbon layer 402 is within about 10%, 5%, 2%, or 1% of the etching rate of the first carbon layer 304.

[0077] As Figure 5 shown, once step 108 is completed, structure 500 is formed. Structure 500 includes a first carbon layer 502 (remaining from the first carbon layer 304) and a second carbon layer 504 (remaining from the second carbon layer 402).

[0078] Step 108 may be performed in a reaction chamber different from or the same as step 104 and / or step 106. The pressure in the reaction chamber in step 108 may be less than 1000 Pa or in the range from about 100 Pa to about 1300 Pa. The temperature in the reaction chamber in step 108 may be less than 100 °C. The plasma power used in step 109 may be in the range from about 200 W to about 4000 W.

[0079] According to other examples of the present disclosure, step 108 may include ion etching. According to these examples, a plasma may be used to form an excited state substance in the reaction chamber. An inert gas may be used to perform ion etching. For example, one or more of hydrogen and nitrogen may be used alone or in combination with one or more of argon and helium in step 108. In a particular example, a mixture of hydrogen and argon (e.g., from about 20 to about 50 volume percent hydrogen and / or from about 50 to about 80 volume percent hydrogen) may be used for ion etching the first carbon layer 304 and the second carbon layer 402.

[0080] To further smooth and / or planarize structure 500, a polishing step (e.g., CMP) may be used to remove or substantially remove the second carbon layer 504 and a portion of the first carbon layer 502 to form structure 600, as Figure 6 shown. Structure 600 includes a first carbon layer 602 that has been planarized using step 108 and / or 110.

[0081] A third layer (e.g., a third carbon layer) may be formed to cover structure 500 and / or structure 600. The chemical composition of the third layer may be the same as or similar to the composition of the second carbon layer 402.

[0082] Figure 7Shows a first comparative example 702 using only the first carbon layer, a second comparative example using the first carbon layer and the second carbon layer formed under the same process conditions, and an example (Example 1) according to an example of the present disclosure using the first carbon layer and the second carbon layer, wherein the density of the first carbon layer is greater than the density of the second carbon layer. For each example, three positions with different feature sizes and pitches on the substrate are shown.

[0083] For Comparative Example 1, the first carbon layer 710 is deposited to cover the feature 708. As shown, the surface of the first carbon layer 710 is relatively rough. For Comparative Example 2, the first carbon layer and the second carbon layer are deposited to cover the feature 708. Then etching is performed, and the third carbon layer is deposited to cover the first carbon layer and the second carbon layer to form the carbon material 712. All three carbon layers have the same or similar compositions. As shown, the surface of the first carbon layer 710 is still relatively rough. Finally, for the example according to the present disclosure, the first carbon layer and the second carbon layer (having a lower density than the first carbon layer) are deposited to cover the feature 708. Then etching is performed, and the third carbon layer (for example, having the same composition as the second carbon layer) is deposited to form the carbon material 714. As shown, the surface of the resulting carbon material (formed using the first carbon layer, the second carbon layer, and the third carbon layer) is relatively smooth even without using a polishing process.

[0084] Figure 10 Shows a reactor system (sometimes simply referred to as a system herein) 1000 according to an exemplary embodiment of the present disclosure. The reactor system 1000 can be used to perform one or more of the steps or sub-steps described herein, and / or to form one or more of the structures or portions thereof described herein.

[0085] System 1000 includes a pair of conductive plate electrodes 4 and 2 that are parallel and face each other within the interior 11 (reaction zone) of reaction chamber 3. By applying, for example, HRF power (e.g., 13.56 MHz or 27 MHz) from power source 25 to one electrode (e.g., electrode 4) and electrically grounding the other electrode (e.g., electrode 2), plasma can be excited within reaction chamber 3. A temperature regulator can be provided in the lower layer 2 (lower electrode), and the temperature of the substrate placed on the lower layer can be maintained at a desired temperature. Electrode 4 can be used as a gas distribution device, such as a shower plate. Reaction gas, dilution gas, (if any) precursor gas, and / or similar gases can be introduced into reaction chamber 3 using one or more of gas line 20, gas line 21, and gas line 22, respectively, and passed through the shower plate 4. Although three gas lines are shown, reactor system 800 can include any suitable number of gas lines. Gas line 20 can be coupled to carbon precursor source 27, gas line 21 can be coupled to inert gas source 28, and gas line 22 can be coupled to another gas source 29.

[0086] In reaction chamber 3, a circular duct 13 with an exhaust gas line 7 is provided through which the gas in the interior 11 of reaction chamber 3 can be exhausted. Additionally, transfer chamber 5 provided below reaction chamber 3 is equipped with a sealed gas line 24 to introduce a sealing gas into the interior 11 of reaction chamber 3 via the interior 16 (transfer zone) of transfer chamber 5, where a partition plate 14 (gate valve is omitted in the figure, through which the wafer is transferred into or out of transfer chamber 5) is provided to separate the reaction zone and the transfer zone. The transfer chamber is also equipped with an exhaust gas line 6. In some embodiments, the deposition step and the processing step are performed in the same reaction space such that two or more (e.g., all) of the steps (e.g., deposition step, steps including processing) can be carried out continuously without exposing the substrate to air or other oxygen-containing atmospheres.

[0087] In some embodiments, a continuous flow of an inert gas or carrier gas into reaction chamber 3 can be achieved using a flow-pass system (FPS), where the carrier gas line is equipped with a bypass line having a precursor reservoir (bottle), and the main line and the bypass line are switched, where the bypass line is closed when only the carrier gas is intended to be supplied to the reaction chamber; while when both the carrier gas and the precursor gas are intended to be supplied to the reaction chamber, the main line is closed, the carrier gas flows through the bypass line and exits the bottle together with the precursor gas. In this way, the carrier gas can continuously flow into the reaction chamber and can carry the precursor gas in a pulsed form by switching between the main line and the bypass line without causing a significant pressure fluctuation in the reaction chamber.

[0088] Those skilled in the art will understand that the apparatus includes one or more controllers 26, which are programmed or otherwise configured to cause one or more of the method steps described herein to be performed. The controller is in communication with the various power sources, heating systems, pumps, robots, and gas flow controllers of the reactor or with valves, as will be understood by those skilled in the art. By way of example, the controller can be configured to control the gas flow of a carbon precursor into at least one of one or more reaction chambers to form a first carbon layer and a second carbon layer covering the first carbon layer, wherein the density of the first carbon layer is greater than the density of the second carbon layer.

[0089] In some embodiments, a dual-chamber reactor (two partitions or compartments for processing wafers that are positioned close to each other) can be used, where the reactive gas and the inert gas can be supplied through a shared pipeline, while the precursor gas is supplied through a non-shared pipeline.

[0090] Since these embodiments are merely examples of embodiments of the present invention, the above-described exemplary embodiments of the present disclosure do not limit the scope of the present invention. Any equivalent embodiments can be considered to be within the scope of the present invention. In fact, various modifications of the present disclosure, other than those shown and described herein, such as alternative useful combinations of the elements described, 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 of forming a structure, the method comprising the steps of: Providing a substrate in a reaction chamber, the substrate including one or more grooves formed on a surface of the substrate; Forming a first carbon layer covering the surface; And Forming a second carbon layer covering the first carbon layer; Wherein, the first carbon layer is formed by forming an initial flowable material; Wherein, the first carbon layer fills the one or more grooves to a height above the surface of the substrate; and Wherein, the density of the first carbon layer is greater than the density of the second carbon layer.

2. The method according to claim 1, wherein The density of the first carbon layer is 10% to 50% greater than the density of the second carbon layer.

3. The method according to claim 1, further comprising the step of chemically mechanically polishing the second carbon layer.

4. The method according to claim 1, further comprising the step of chemically mechanically polishing at least a portion of the first carbon layer.

5. The method according to claim 1 further includes the steps of chemically-mechanically polishing the second carbon layer and chemically-mechanically polishing at least a portion of the first carbon layer, wherein, The chemical mechanical polishing rate of the first carbon layer is less than the chemical mechanical polishing rate of the second carbon layer.

6. The method according to claim 1, wherein, The step of forming the first carbon layer includes a plasma process.

7. The method according to claim 1, wherein The step of forming the second carbon layer includes a plasma process.

8. The method according to claim 1, further comprising a plasma treatment step for treating the first carbon layer.

9. The method according to claim 1, further comprising a plasma treatment step for treating the second carbon layer.

10. The method according to claim 1, wherein The temperature in the reaction chamber during the step of forming the first carbon layer is less than 100 °C.

11. The method according to claim 1, wherein, The temperature in the reaction chamber during the step of forming the second carbon layer is less than 100 °C.

12. The method according to claim 1, wherein, The step of forming the first carbon layer includes providing a carbon precursor to the reaction chamber, wherein the chemical formula of the carbon precursor is represented by C x H y N z , where x is a natural number of 2 or greater, y is a natural number, and z is 0 or a natural number.

13. The method according to claim 1, wherein, The step of forming the second carbon layer includes providing a carbon precursor to the reaction chamber, wherein the chemical formula of the carbon precursor is represented by C x H y N z , where x is a natural number of 2 or greater, y is a natural number, and z is 0 or a natural number.

14. The method according to any one of claims 12 and 13, wherein The carbon precursor includes a cyclic structure.

15. The method according to claim 14, wherein The cyclic structure includes double bonds.

16. The method according to claim 1, further comprising the step of etching the second carbon layer.

17. The method according to claim 1, further comprising the step of etching the first carbon layer.

18. The method according to claim 17 further includes the step of etching the second carbon layer, wherein, The steps of etching the first carbon layer and the second carbon layer include non-selectively etching the second carbon layer and the first carbon layer.

19. The method according to any one of claims 16 - 18, wherein, The steps of etching the first carbon layer and the second carbon layer include ion etching.

20. The method according to claim 1, wherein The hardness of the first carbon layer is greater than the hardness of the second carbon layer.

21. The method according to claim 1, further comprising the step of forming a third layer covering the second carbon layer.

22. A structure formed by the method according to claim 1.

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