Method for forming high aspect ratio features - Patents.com

Abstract

To disclose methods and systems for forming high aspect ratio features on a substrate.SOLUTION: Exemplary methods include forming a first carbon layer within a recess, etching a portion of the first carbon layer within the recess, and forming a second carbon layer within the recess. Structures formed using the methods or systems are also disclosed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to methods of forming structures suitable for use in the manufacture of electronic devices. More specifically, embodiments of the present disclosure relate to methods of forming structures including high aspect ratio features using carbon-containing materials. [Background technology]

[0002] During the manufacture of devices such as semiconductor devices, it is often desirable to form structures having high aspect ratio features (e.g., high aspect ratio trenches or gaps). Several techniques for forming the features include patterning, etching, and masking layer removal. In some cases, features having aspect ratios of more than 50 or even 60 can be achieved.

[0003] Etching of silicon-containing materials can be used to form a variety of features. A comparative process 500 for forming features is shown in FIG. 5, where FIG. 5(a) shows the result of step S502 providing an intermediate structure 522 having a masking layer 532 deposited thereon. The intermediate structure 522 comprises a substrate 524 having one or more (e.g., a plurality of) layers 526 deposited thereon. The masking layer 532 covers a top layer 530 of the one or more layers 526. The one or more layers 526 may include, for example, alternating layers. As shown in FIG. 5, the one or more layers 526 may include one or more silicon dioxide (SiO2) layers 560 alternating with one or more silicon nitride (SiN) layers 528, although other configurations are possible, including single layers or layers including other materials. The top layer 530 may be a layer of SiO2, SiN, or other materials.

[0004] As shown in FIG. 5(b), after the patterning step S504, the masking layer 532 has an unmasked opening 534 therein. As shown in FIG. 5(c), after etching and removing the masking layer 532 in step S506, a feature 536 is formed in the intermediate structure 522 to form the intermediate structure 523. As shown in FIG. 5(d), after the carbon filling step S508, a carbon-containing material 538 covers the surface of the intermediate structure 523 and is in the feature 536. As shown in FIG. 5(e), after the carbon etching step S510, the feature 536 is filled with a remaining portion of the carbon-containing material 540. The remaining portion of the carbon-containing material 540 protects the feature 536 from being filled with unwanted material during subsequent steps. As shown in FIG. 5(f), after the step S512 of depositing one or more additional layers 542 with a top layer 544 to produce an intermediate structure 582, the feature 536 remains filled with the remaining portion of the carbon-containing material 540, thereby protecting the feature 536 from being filled with the material deposited in the additional layer deposition step S512 and protecting the integrity of the intermediate structure 582. As described above, the one or more additional layers 542 may include one or more SiO2 layers 584, optionally alternating with one or more SiN layers 582. As shown in FIG. 5(g), after the step S514 of masking layer deposition, a masking layer 546 is on the surface of the top layer 544 of the one or more additional layers 542. As shown in FIG. 5(h), after the step S516 of patterning, an opening 548 appears in the masking layer 546. As shown in Figure 5(i), after the additional layer etching step S518, there is an opening 550 above the remaining portion of the carbon-containing material 540 in the feature 536. Also, as shown in Figure 5(j), after the masking layer and carbon layer removal step S520, there is a (feature) recess 552, which includes the feature 536 and the opening 550 formed in the etching steps S506 and S518, respectively.

[0005] While the process illustrated in FIG. 5 can be effective in forming various features, problems remain including poor filling of recesses, resulting bowing, and low throughput, as illustrated in FIGS. 6 and 7. An example of poor filling is illustrated in FIG. 6. As illustrated in FIG. 6, a structure 602 having one or more (e.g., multiple) layers 606 on a substrate 604 has a carbon-containing material 612 deposited thereon. The one or more layers 606 may include, for example, alternating SiO2 layers 610 and / or SiN layers 608, although other configurations are possible. An upper layer 620 of the one or more layers 606 has a surface that is underlain by a carbon-containing material 612. The carbon-containing material 612 may fail to properly fill the recesses 614, resulting in the formation of a bottleneck where the carbon-containing material fails to cover the opening of the recesses 614 after partial removal back to the upper surface of the surface of the upper layer 620 of the carbon layer. The bottleneck may cause over-etching and / or bowing during a subsequent etching step.

[0006] As shown in FIG. 7, the structure 702 has one or more (e.g., multiple) layers 706 formed on a substrate 704. The one or more (e.g., multiple) layers 706 may include alternating SiO2 layers 710 and / or SiN layers 708, although other configurations are possible. As shown in FIG. 7(a), a carbon-containing layer 712 covers the structure 702 and is within a recess 714. As shown in FIG. 7(b), the structure 702 has a height h. As the height h increases, the time required to deposit the carbon-containing material and / or the time it takes to remove the carbon-containing layer 712 increases, resulting in poor throughput. Thus, while complete filling of the recess 714 may avoid over-etching, output failures may also occur because high aspect ratio features may require extended periods of carbon deposition and / or complete removal of the carbon layer from the recess.

[0007] All descriptions, including descriptions of problems and solutions described in this section, are included in this disclosure solely for the purpose of providing a background for the disclosure and should not be construed as an admission that any or all of the descriptions were known at the time the invention was made or that they constitute prior art. Summary of the Invention [Problem to be solved by the invention]

[0008] Various embodiments of the present disclosure relate to methods of fabricating structures having high aspect ratio features suitable for use in forming electronic devices. While the manner in which the various embodiments of the present disclosure address shortcomings of previous methods and structures is described in more detail below, generally, exemplary embodiments of the present disclosure provide improved methods for forming features on a surface of a substrate having a carbon-containing material and / or for forming a layer or structure that includes carbon. The exemplary methods may prevent or reduce bowing during the formation of the structures and / or may exhibit relatively high throughput, for example, by reducing carbon deposition and / or etching times. [Means for solving the problem]

[0009] According to various embodiments of the present disclosure, methods of fabricating a structure (e.g., a structure including one or more high aspect ratio features) are provided. Exemplary methods may include providing a substrate in a reaction chamber of a reactor, the substrate including one or more layers including a surface and a recess formed in the one or more layers, forming a first carbon layer on the surface thereby partially filling the recess, where the first carbon layer may be initially flowable, partially removing a portion of the first carbon layer in the recess, and forming a second carbon layer covering a remaining portion of the first carbon layer. The second carbon layer may also be initially flowable. The initial flowability of the first carbon layer may be greater than the initial flowability of the second carbon layer. In some exemplary methods, etching a portion of the first carbon layer may include etching the first carbon layer until a surface of the first carbon layer in the recess is below a top of the recess. An exemplary method may further include the steps of partially removing (e.g., etching) the second carbon layer, where the remaining portion of the second carbon layer is flush or substantially flush with the opening of the recess, depositing at least one additional layer covering the remaining portion of the second carbon layer, etching the at least one additional layer to form an opening in the remaining portion of the second carbon layer, and removing the remaining portion of the second carbon layer and the remaining portion of the first carbon layer, thereby forming the high aspect ratio feature. In some cases, the first carbon layer may have a top surface that may initially extend (e.g., may be flush or substantially flush) to at least a top surface of the recess. According to further embodiments of the present disclosure, the second carbon layer may fill the recess to at least a top surface of the substrate. Etching a portion of the second carbon layer may also include etching the second carbon layer until a surface of the second carbon layer within the recess is flush or substantially flush with a surface defining the recess opening. Exemplary methods can include a treatment that can include a plasma treatment, such as treatment with species formed from one or more of argon, helium, nitrogen, and hydrogen. The treatment, such as a plasma treatment, can be part of the first and / or second carbon layer formation steps.The various etching steps can be performed using one or more steps of plasma etching, for example, one or more plasma enhanced etching processes.

[0010] According to yet a further exemplary embodiment of the present disclosure, a structure is formed, at least in part, according to the methods described herein.

[0011] According to yet a further exemplary embodiment of the present disclosure, a system is provided for carrying out the methods described herein and / or for forming the structures described herein.

[0012] These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of specific embodiments which refer to the accompanying drawings, and the invention is not limited to any particular embodiment disclosed.

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

[0014] [Figure 1] 1 illustrates a process for fabricating a structure including high aspect ratio features according to an embodiment of the present disclosure. [Diagram 2] 1A-1C illustrate schematic diagrams of structures having features with vertically aligned sidewalls according to exemplary embodiments of the present disclosure; [Diagram 3] 1A and 1B are schematic diagrams illustrating structures having features with substantially vertically aligned sidewalls having a lip. [Figure 4] 1 illustrates a schematic of a structure having vertically aligned sidewalls with overhangs. [Diagram 5] 1 illustrates a comparative process for forming features in a structure using a single carbon-containing material. [Figure 6]1 illustrates the incomplete filling of a recess with a carbon-containing material. [Figure 7] 1 illustrates a high aspect ratio feature filled with a carbon-containing material. [Figure 8] 1 illustrates a system according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] It will be appreciated that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale, for example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of the illustrated embodiments of the present disclosure.

[0016] Although certain specific embodiments and examples are disclosed below, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention, as well as obvious modifications and equivalents thereof, and therefore it is not intended that the scope of the disclosed invention should be limited by the specific disclosed embodiments described below.

[0017] The present disclosure generally relates to methods of depositing materials, methods of forming structures and features, structures and features formed using the methods, and systems for performing the methods and / or for forming structures and / or features. By way of example, the methods described herein may be used to form structures including features such as recesses or gaps (e.g., trenches or vias). Forming the features may include masking or blocking (e.g., at least partially filling) an existing feature, such as a recess, with a material, such as a carbon-containing (e.g., organic) material to form a base over which additional layers may be deposited. As used herein, the terms gap and recess may be used interchangeably.

[0018] Incomplete (partial) filling of recesses with carbon-containing material may result in the formation of voids. The embodiments disclosed herein utilize void formation to provide an effective carbon base, thereby enabling efficient formation of structures including high aspect ratio features, such as recesses. In some embodiments disclosed herein, features including aspect ratios of 60-70, for example, may be formed. In some embodiments, high throughput may be achieved. In some embodiments, bowing and / or over-etching may be mitigated or even avoided.

[0019] In this disclosure, "gas" can refer to a material that is a gas, vaporized solid, and / or vaporized liquid at ambient temperature and pressure, and may be comprised 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 a gas distribution assembly, e.g., a showerhead, other gas distribution device, etc., may be used, for example, to seal a reaction chamber, which reaction chamber includes a seal gas, e.g., a noble gas. In some cases, such as in the context of material deposition, the term "precursor" can refer to a compound that participates in a chemical reaction that produces another compound, particularly a compound that constitutes the membrane matrix or backbone of the membrane, and the term "reactant" can refer to a compound that activates the precursor, modifies the precursor, or catalyzes the reaction of the precursor, in some cases other than the precursor, e.g., when radio frequency (RF) power is applied, the reactant can provide elements (e.g., O, H, N, C) to the membrane matrix and become part of the membrane matrix. In some cases, the terms "precursor" and "reactant" can be used interchangeably. The term "inert gas" refers to a gas that does not participate to any significant extent in the chemical reaction and / or a gas that, for example, when RF power is applied, excites the precursors, but, unlike the reactants, may not become part of the film matrix to any significant extent.

[0020] The term "substrate" as used herein may refer to any underlying material or material that may be used to form a device, circuit, or film, or any underlying material or material on which a device, circuit, or film may be formed. The substrate may include a bulk material, such as silicon (e.g., single crystal silicon), other Group IV materials, such as germanium, or compound semiconductor materials, such as GaAs, and may include one or more layers above or below the bulk material. Additionally, the substrate may include various features, such as gaps (e.g., recesses or vias), lines or protrusions, such as lines with gaps formed therebetween, and the like, formed in or on at least a portion of the layer or bulk material of the substrate. By way of example, the one or more features may have a width of about 100 nm to about 200 nm, a depth or height of about 5,000 nm to about 15,000 nm, and / or an aspect ratio of about 25 to about 150. As a further example, the substrate may include a bulk material and one or more layers of, for example, silicon oxide and silicon nitride overlying the bulk material. One or more of the layers may include a recess and a surface.

[0021] In some embodiments, a "film" refers to a layer extending in a direction perpendicular to the thickness direction. In some embodiments, a "layer" refers to a material having a particular thickness formed on a surface, and may be a synonym of a film, or a non-film structure. A film or layer may be composed of a separate single film or layer or multiple films or layers having particular properties, and the boundaries between adjacent films or layers may or may not be distinct, and may or may not be defined based on any physical, chemical, and / or other characteristics, formation process or order, and / or function or purpose of the adjacent films or layers. A layer or film may or may not be continuous.

[0022] As used herein, the term "carbon layer" or "carbon-containing material" may refer to a layer or material whose chemical formula can be expressed as including carbon. A layer that includes a carbon-containing material may include other elements, such as one or more of nitrogen and hydrogen.

[0023] As used herein, the term "structure" can refer to a partially or fully fabricated device structure. By way of example, a structure can include a substrate upon which one or more layers and / or features are formed.

[0024] Plasma enhanced chemical vapor deposition (PECVD) can refer to a process used to deposit thin films from a gaseous state (vapor) to a solid state on a substrate. A chemical reaction is involved in this process and occurs after the generation of plasma of the reactive gas. The plasma can be applied to a space filled with reactive and / or inert gases. In some embodiments, a radio frequency (RF) plasma source is used to generate the plasma, but any type of plasma source capable of generating direct and / or remote plasma can be used, including microwave and DC sources. In some embodiments, a remotely generated plasma can be used to supply the reactive species. In further embodiments (e.g., pulsed PECVD), only one of the reactants, either the precursor or the reactive species, can be continuously provided to the chamber, while the other reactant is intermittently pulsed.

[0025] In this disclosure, "continuously" refers to without breaking vacuum, without interruption in the time sequence, without any intervening material steps, without changing process conditions immediately following a subsequent step, or, in some embodiments or circumstances, without any intervening distinct physical or chemical structures between the two structures other than the two structures themselves.

[0026] The liquidity (e.g., initial liquidity) may be determined as follows:

[0027] [Table 1]

[0028] B / T refers to the ratio of the thickness of the film deposited at the bottom of the recess to the thickness of the film deposited on the top surface where the recess is formed before the recess is filled or partially filled. Generally, the higher the aspect ratio of the recess, the higher the B / T ratio, so wide recesses with aspect ratios of about 1 or less are typically used to evaluate flowability. The B / T ratio can be higher when the aspect ratio of the recess is higher. As used herein, a "flowable" film or material exhibits good or better flowability.

[0029] As described in more detail below, film fluidity may be achieved temporarily, for example, when a volatile hydrocarbon precursor is polymerized by the plasma and deposited on the surface of a substrate, where the gaseous precursor is activated or fragmented by energy provided by the plasma gas discharge to initiate polymerization, and the resulting polymeric material is deposited on the surface of the substrate, where the material exhibits temporary fluid behavior. In some cases, when the deposition process is completed, the fluid film is no longer fluid (or exhibits reduced fluidity) and solidifies, and therefore a separate solidification process may not be employed.

[0030] In this disclosure, any two variables may constitute a workable range for that variable, and any range stated may include or exclude the endpoints. In some embodiments, further, any value of a stated variable (whether they are stated as "about" or not) may refer to an exact or approximate value, may include equivalents, may refer to an average, a median, a representative value, or a majority, etc. Furthermore, in this disclosure, the terms "comprise", "comprise", "have", and "have" may, in some embodiments, independently refer to "typically or broadly include", "comprise", "consist essentially of", or "consist of". In this disclosure, any defined meaning, in some embodiments, does not necessarily exclude the ordinary and customary meaning.

[0031] 1 illustrates a method 100 for forming a structure including high aspect ratio features using two or more carbon-containing layers. During step S102, a first intermediate structure 122 including a substrate 124 is provided within a reaction chamber of a reactor.

[0032] As shown in FIG. 1(a), during step S102, a first intermediate structure 122 having a substrate 124 is provided in a reaction chamber of a reactor. The first intermediate structure 122 includes a first one or more (e.g., multiple) layers 126 having a recess 138 formed therein. The first one or more (e.g., multiple) layers 126 may include, for example, one or more alternating layers. Illustratively, the first one or more layers 126 may include one or more silicon oxide layers 128 alternating with one or more silicon nitride layers 130. Other configurations are possible. The first one or more layers 126 (e.g., silicon oxide and / or silicon nitride layers) may be deposited by any suitable process, such as CVD, PECVD, or PEALD. Although illustrated with reference to multiple layers 126, the first intermediate structure 122 may include a single layer of material instead of multiple layers 126. Although illustrated with silicon oxide and / or silicon nitride as layer materials, other materials may be used. The first intermediate structure 122 can serve as a substrate for subsequent processes.

[0033] The first intermediate structure 122 has a first top layer 132. A recess 138 may be formed in the first one or more layers 126 using the techniques described above, such as, for example, masking, patterning, and etching techniques. The recess 138 has a recess sidewall 134 and an opening 136. In some embodiments, the recess sidewall 134 may be vertical or substantially vertical. In some embodiments, the opening 136 is flush or substantially flush with a surface of the first top layer 132 of the first one or more (e.g., layers) 126.

[0034] 1(b), after the first step S104 of depositing a carbon-containing material, the first intermediate structure 122 has deposited a first carbon-containing material 140 on the first top layer 132, the first carbon-containing material 140 being flowable to partially fill the recess 138 and form a void 142 below a portion of the first carbon-containing material 140 in the recess 138. An exemplary technique for depositing the first carbon-containing material 140 on the first intermediate structure 122 during step S104 includes a PECVD technique.

[0035] The PECVD technique used during the step of depositing the first carbon-containing material 140 may include introducing a suitable precursor into the reaction chamber while applying RF power to form a plasma in the reaction chamber. The frequency of the RF power may range from about 2.0 MHz to about 27.12 MHz and may have a power of about 50 W to about 300 W. In some embodiments, a direct current (DC) or RF bias may be applied through an electrode, such as, for example, one or more of the susceptor and / or the gas distributor. In some such cases, an RF frequency may be applied to the susceptor stage / susceptor during at least a portion of step S104. The RF frequency applied to the susceptor stage / susceptor during step S104 may range from about 400 kHz to about 800 kHz. One or more inert gases may be introduced into the reaction chamber during the step of depositing the first carbon-containing material 140. The one or more inert gases may include argon, helium, nitrogen, and / or hydrogen.

[0036] As described above, a precursor may be introduced into the reaction chamber during step S104. A suitable precursor is a compound represented by the formula C x H y N zwhere x can be a natural number equal to or greater than 2, y can be a natural number, and z can be zero or a natural number. For example, x can range from about 2 to about 15, y can range from about 4 to about 30, and z can range from about 0 to about 10. Additionally or alternatively, the precursor can be a chain or cyclic molecule having two or more carbon atoms and one or more hydrogen atoms, such as a molecule of formula C x H y N z According to certain examples, the precursor may be or may include one or more double bonds, and / or one or more aromatic hydrocarbon structures.

[0037] In some embodiments, the first carbon-containing material 140 may have high fluidity and low etch selectivity. Etch selectivity refers to the ratio of the etch rate of one material to another. In some embodiments, the etch selectivity of the carbon-containing material 140 to the material of the first one or more (e.g., multiple) layers 126 is low, e.g., less than 2.0. The initial fluidity of the first carbon-containing material 140 may be greater than "very good" as defined in Table 1.

[0038] In addition to depositing the first carbon-containing material 140, step S104 may optionally include a treatment step. In some embodiments, step S104 may not include a plasma treatment or may include a weak plasma treatment. The weak plasma treatment may include contacting the first carbon-containing material with an inert gas, such as one or more of argon, helium, nitrogen, and / or hydrogen, while applying RF power to form excited species from one or more of argon, helium, nitrogen, and / or hydrogen. In some embodiments, the weak plasma treatment in step S104 may include exposing the first intermediate structure 122 to a plasma having an RF power (e.g., continuous) of about 50 W to about 300 W. The RF frequency used in step S104 may be about 2.0 MHz to about 27.12 MHz. In some embodiments, the exposure of the first carbon-containing material 140 to the plasma during the treatment step of step S104 may range from about 1 to 10 seconds, such as about 1.0 to about 10.0 seconds. (Second may be abbreviated herein as "sec.".) During step S104, the temperature within the reaction chamber may be less than 100°C.

[0039] As shown in FIG. 1(c), after the first partial carbon layer removal step S106, the remaining portion of the first carbon-containing material 144 remains in the recess 138. A void 142 may be formed below the remaining portion of the first carbon-containing material 144. Thus, the remaining portion of the first carbon-containing material 144 forms the void 142 in the recess 138. In some embodiments, a portion of the recess 138 above the remaining portion of the first carbon-containing material 144 may remain open after the first partial carbon layer removal step S106. Plasma etching may be used for the partial carbon layer removal during step S106. An etchant may be flowed into the reaction chamber during step S106. Exemplary etchants include oxygen-containing gases such as oxygen (O2) or N2O, or hydrogen-containing gases such as hydrogen (H2) or NH3. The plasma may generate oxygen and / or hydrogen containing active species during step S106. In some cases, the gas used during step S106 may include about 5.0% to about 50.0% oxygen-containing gas and / or hydrogen-containing gas in an inert gas such as helium, argon, etc. The flow rate of the gas (e.g., oxygen-containing gas, hydrogen-containing gas, and / or any inert gas) during step S106 may range from about 1.0 slm to about 4.0 slm.

[0040] Activated species may be formed from a gas (e.g., an oxygen-containing gas, a hydrogen-containing gas, and / or any inert gas) during step S106 using direct and / or remote plasma. The power applied to the electrodes during step S106 may range from about 50 W to about 400 W. The frequency of the power applied during step S106 may range from about 2.0 MHz to about 27.12 MHz.

[0041] As shown in FIG. 1(d), after a second step S108 including depositing the second carbon-containing material 146, the recess 138 is partially filled with the second carbon-containing material 146, which may be deposited on the surface 176 of the top layer 132 of the first one or more layers 126. Exemplary techniques for depositing the second carbon-containing material 146 on the top layer 132 of the first one or more layers 126 during step S108 include PECVD techniques. The PECVD technique used during the step of depositing the second carbon-containing material 146 may include introducing a suitable precursor into the reaction chamber while applying RF power to form a plasma in the reaction chamber. The frequency of the RF power may range from about 2.0 MHz to about 27.12 MHz and may have a power of about 50 W to about 300 W. In some embodiments, a direct current (DC) or RF bias may be applied through an electrode, such as, for example, one or more of the susceptor and / or gas distributor. In some such cases, an RF frequency may be applied to the susceptor stage / susceptor during at least a portion of step S108. The RF frequency applied to the susceptor stage / susceptor during step S108 may range from about 400 kHz to about 800 kHz. In some embodiments, the film density of the carbon layer may be adjusted, controlled, or manipulated, for example, by manipulating one or more of radio frequency (RF) power, exposure time to plasma, or bias RF power, as applied to the susceptor stage / susceptor.

[0042] One or more inert gases may be introduced into the reaction chamber during step S108 of depositing the second carbon-containing material 146. The one or more inert gases may include argon, helium, nitrogen, and / or hydrogen.

[0043] During step S108, a precursor may be introduced into the reaction chamber. A suitable precursor for depositing the second carbon-containing material 146, which may be the same or different as that used to deposit the first carbon-containing material 140, is represented by the formula C: x H y N zwhere x can be a natural number equal to or greater than 2, y can be a natural number, and z can be zero or a natural number. For example, x can range from about 2 to about 15, y can range from about 4 to about 30, and z can range from about 0 to about 10. Additionally or alternatively, the precursor can be a chain or cyclic molecule having two or more carbon atoms and one or more hydrogen atoms, such as a molecule of formula C x H y N z According to certain examples, the precursor may be or may include one or more double bonds, and / or one or more aromatic hydrocarbon structures.

[0044] In some embodiments, the second carbon-containing material 146 may have a lower fluidity and / or a higher etch selectivity compared to the first carbon-containing material 140. Etch selectivity refers to the ratio of the etch rate of one material to another. In some embodiments, the etch selectivity of the second carbon-containing material 146 to the materials of the one or more (e.g., multiple) additional layers 152 (see description at the bottom of FIG. 1(f)) is relatively high, e.g., greater than 2.0. The initial fluidity of the carbon-containing material 146 may be less than "good" as defined in Table 1.

[0045] In some embodiments, after depositing the second carbon-containing material 146, step S108 may also include a plasma treatment step. In some embodiments, the treatment step may include a strong plasma treatment. Continuous radio frequency (RF) may be used during step S108. The strong plasma treatment may include contacting the second carbon-containing material 146 with activated species formed from an inert gas, such as one or more of argon, helium, nitrogen, and / or hydrogen, by exposing the gas to a plasma. In some exemplary embodiments, the strong plasma treatment during step S108 may include exposing the second carbon-containing material 146 to a plasma having an RF power (e.g., continuous) of about 50 W to about 300 W. The RF frequency used during step S108 may be about 2.0 MHz to about 27.12 MHz. In some embodiments, the exposure of the second carbon-containing material 146 to the plasma during the treatment step of step S108 may range from about 5 to 30 seconds, such as about 5.0 to about 30.0 seconds. (Second may be abbreviated herein as "sec.".) During step S108, the temperature within the reaction chamber may be less than 100°C.

[0046] As shown in FIG. 1(e), after the step S110 of partial removal of the second carbon-containing material 146, a remaining portion of the second carbon-containing material 148 having a surface 150 remains in the recess 138, and the first top layer 132 has a first top surface 176. Plasma etching may be used during the partial removal of the second carbon-containing material during step S110. An etchant may be flowed into the reaction chamber during step S110. An exemplary etchant used in step S110 may include an oxygen-containing gas, such as oxygen (O2), and a hydrogen-containing gas, such as hydrogen (H2). In some such cases, the gas used in step S110 may include about 5.0% to about 50.0% of an oxygen-containing gas and / or a hydrogen-containing gas in an inert gas, such as helium, argon, and the like. The flow rate of the gas (e.g., the oxygen-containing gas, the hydrogen-containing gas, and / or any inert gas) in step S110 may range from about 1.0 slm to about 4.0 slm.

[0047] Activated species may be formed from a gas (e.g., an oxygen-containing gas, a hydrogen-containing gas, and / or any inert gas) using direct and / or remote plasma in step S110. The power applied to the electrodes during step S110 may range from about 100 W to about 800 W. The frequency of the power used in step S110 may range from about 2.0 MHz to about 27.12 MHz.

[0048] In some embodiments, after S110, a surface 150 of the remaining portion of the second carbon-containing material 148 remaining in the recess 138 is flush or substantially flush with the first top surface 176 of the first top layer 132 of the first one or more layers 126. In some embodiments, the remaining portion of the second carbon-containing material 148 in the recess 138 after step S110 blocks the remaining portion of the first carbon-containing material 144 and the remaining portion of the second carbon layer 148 from depositing material in the recess 138 and the void 142 during later process steps, e.g., steps S112-S118 as shown.

[0049] As used herein, "coplanar" means that the surface of one feature (e.g., a second carbon layer) is coplanar with the surface of another feature (e.g., a structure) within the limits of conventional measurement methods such as cross-sectional TEM or SEM. As used herein, "substantially coplanar" means that the surface of a first feature is no more than five percent (5%) higher or lower than the surface of a second (reference) feature, where the height difference between the two surfaces is the numerator and the thickness of the thinner of the two features is the denominator. In some embodiments, surface 150 of the remaining portion of second carbon-containing material 148 formed in step S110 is “substantially coplanar” with first upper surface 176 of first upper layer 132, meaning that it may be 5% or less, 4%, 3%, 2%, 1%, 0.5%, 0.25%, 0.1%, 0.05%, or 0.01% higher or lower than first upper surface 176 (if first upper layer 132 is thinner than the remaining portion of second carbon-containing material 148, first upper layer 132 is the reference layer whose width is the denominator).

[0050] As shown in FIG. 1(f), after step S112 of depositing the additional layer 152 on the first top layer 132 of the first one or more (e.g., multiple) layers 126 and on the surface 150 of the remaining portion of the second carbon-containing material 148, one or more (e.g., multiple) additional layers 152 are formed, thereby forming a second intermediate structure 182. The one or more additional layers 152 formed in step S112 have a top layer 154 having a surface 156. As shown in FIG. 1(f), after depositing step S112 of the one or more additional layers 152, the remaining portion of the first carbon-containing material 144 and the remaining portion of the second carbon-containing material 148 remain in the recess 138. The void 142 remains under the remaining portion of the first carbon-containing material 144, thereby protecting the recess 138 from filling with the material deposited in the additional layer deposition step S112. The one or more additional layers 152 may be formed by any suitable process, such as CVD, PECVD, or PEALD.

[0051] 1(g), after the masking layer deposition step S114, a masking layer 158 is formed on the surface 156 of the top layer 154. Suitable masking layer materials may include SiC, metal oxides (TiO, ZrO, AlO, etc.), or organic layers and may be deposited by methods such as CVD, PECVD, or PEALD.

[0052] 1(h), after the patterning step S116, which includes partial masking layer removal, there are exposed portions 160 of the surface 156 of the top layer 154 of the one or more (e.g., multiple) additional layers 152. Patterning may be performed by any suitable method, such as lithography.

[0053] 1(i), after etching step S118, an opening 162 is formed in the one or more (e.g., multiple) additional layers 152. The opening 162 has opening sidewalls 164. Step S118 may include the same or similar techniques as those described above in connection with step S102.

[0054] As shown in FIG. 1(j), after masking layer and carbon layer removal step S120, feature 166 is formed. Feature 166 formed in step S120 has feature sidewalls 170. Feature 166 includes both recess 138 and opening 162. Thus, the second etching step S118, in combination with carbon layer removal in step S120, has formed a single high aspect ratio feature 166 in first one or more layers 126 and one or more additional layers 152, thereby forming structure 192 having feature 166 with high aspect ratio. Masking layer may be removed by any suitable method, such as wet process (use of HF or H2O2-NH4OH based chemistries) or dry process (plasma etching with CF or Cl based chemistries). The remaining portions of the second carbon-containing layer 148 and the remaining portions of the first carbon-containing material 144 may be removed using the techniques described above, e.g., carbon layer plasma etching, as described with respect to steps S106 and / or S110.

[0055] The combination of the remaining portion of the second carbon-containing material 148 with the remaining portion of the first carbon-containing material 144 (e.g., having the void 142 below the remaining portion of the first carbon-containing material 144) effectively blocks deposition of material during processing steps (e.g., steps S112, S114, S116, and S118). The combination of the remaining portion of the second carbon-containing material 148 with the remaining portion of the first carbon-containing material 144 (e.g., having the void 142 below the remaining portion of the first carbon-containing material 144) may be more easily and / or quickly removed than a comparative carbon-containing material, such as the carbon-containing material 714 shown in FIG. 7. Thus, method 100 and related methods within the scope of the present invention may achieve a higher throughput than comparative method 500. Without wishing to be bound by theory, such higher throughput may be achieved because the remaining portion of the first carbon-containing material 144 (e.g., having high fluidity and low etch selectivity) and the remaining portion of the second carbon-containing material 148 (e.g., having low fluidity and / or high etch selectivity relative to the first carbon-containing material) taken together are more easily and / or quickly deposited and / or removed than a comparative carbon-containing material that includes only one carbon-containing material and / or does not have the voids 142 below the remaining portion of the first carbon-containing material 144 that promote void formation. Thus, again without wishing to be bound by theory, it is believed that methods of the present invention, such as method 100 shown in FIG. 1, that use two carbon-containing materials and optionally include voids may achieve higher throughput than a comparative method that uses a single carbon-containing material.

[0056] 2-4, structure 222 has formed therein feature 266. As shown in FIG. 2, feature 266 has feature sidewalls 270, including aperture sidewall 264 and recess sidewall 234. Aperture sidewall 264 and recess sidewall 234 meet at junction 202 between first top layer 232 of first one or more layers 226 and second one or more additional layers 252. First top layer 232 of first one or more layers 226 has a thickness w.

[0057] As shown in FIG. 2, in some embodiments, the recess sidewall 234 and the opening sidewall 264 are vertically aligned or substantially vertically aligned such that there is a seamless or substantially seamless joint 202 between the recess sidewall 234 and the opening sidewall 264.

[0058] 3, there is a structure 322 in which the feature sidewall 270 may include a lip 372 resulting from a slight misalignment of the opening sidewall 264 and the recess sidewall 234. In such a case, the variance of the lip v 1 may be present, which is the horizontal distance along the lip 372 between the opening sidewall 264 and the recess sidewall 234.

[0059] 4, there is a structure 422 in which the feature sidewall 270 may include an overhang 474 caused by a slight misalignment of the opening sidewall 264 and the recess sidewall 234. In such a case, the variance of the overhang v 11 may be present, which is the horizontal distance along the overhang between the opening sidewall 264 and the recess sidewall 234.

[0060] Although FIG. 3 illustrates a lip 272 and FIG. 4 illustrates an overhang 474, the structure 322, 422 may have both a lip 272 and an overhang 474 in the case of slight misalignment, thus reducing the lip variance v 1 and the variance of the overhang v 11 It will be appreciated that the present invention may have both.

[0061] As used herein, "vertically aligned" means that there is no lip or overhang at the feature sidewall 270 that is measurable by conventional methods (e.g., CVD or ALD), and "substantially vertically aligned" means that there is no lip variance v as measured by conventional methods. 1 and / or variance of the overhang v 11 is less than about 3% of the thickness w of the first top layer 232 of the first one or more layers 226. In some embodiments, the lip variance v 1and / or variance of the overhang v 11 may be less than about 3% of the thickness w of the first top layer 232, as measurable by routine methods.

[0062] As used herein, "seamless" means that the feature sidewalls are free of lips or overhangs measurable by conventional methods (such as PECVD or PEALD). As used herein, "substantially seamless" means that the variance of the lips, v, is zero, as measurable by conventional methods. 1 and / or variance of the overhang v 11 is less than about 5% of the thickness w of the first top layer 232 of the first one or more layers 226. In some embodiments, the lip variance v 1 and / or variance of the overhang v 11 may be less than about 3% of the thickness w of the first top layer 232.

[0063] The structure 192 illustrated in FIG. 1(j), and the structures 222, 322, 422 illustrated in FIGS. 2-4, respectively, may serve as substrates in subsequent processing, including repeating the method illustrated in FIG.

[0064] The method 100 shown in FIG. 1 can be carried out in a reactor system 600, as shown in FIG. 6, which can be used to perform one or more of the steps or substeps described herein and / or to form one or more structures or portions thereof described herein.

[0065] 6 illustrates a reactor system 600 according to an exemplary embodiment of the present disclosure. The reactor system 600 may be used to perform one or more of the processes or sub-processes described herein and / or to form one or more structures or portions thereof described herein.

[0066] The reactor system 600 includes a pair of conductive flat plate electrodes 4, 2 parallel and facing each other in the interior 11 (reaction zone) of the reaction chamber 3. A plasma can be excited in the reaction chamber 3, for example, by applying HRF power (e.g., 2.0 MHz to 27.12 MHz) from a power source 25 to one electrode (e.g., electrode 4) and electrically grounding the other electrode (e.g., electrode 2). The lower stage 2 (lower electrode) is provided with a temperature regulator, and the temperature of the substrate 1 disposed thereon can be kept constant at a desired temperature. The electrode 4 can function as a gas distribution device, such as a shower plate. The reactant gas, diluent gas (if present), precursor gas, and / or etchant can be introduced into the reaction chamber 3 through the gas distribution device 4 using one or more of gas line 20, gas line 21, and gas line 22, respectively. Although illustrated with three gas lines, the reactor system 600 can include any suitable number of gas lines.

[0067] The reaction chamber 3 is provided with a circular duct 13 having an exhaust line 7 through which gas in the interior 11 of the reaction chamber 3 can be exhausted. In addition, the transfer chamber 5 arranged below the reaction chamber 3 is provided with a seal gas line 24 for introducing a seal gas into the interior 11 of the reaction chamber 3 through the interior 16 (transfer zone) of the transfer chamber 5, and is provided with a separation plate 14 for separating the reaction zone from the transfer zone (a gate valve through which the wafer is transferred in and out of the transfer chamber 5 is omitted from this figure). The transfer chamber is also provided with an exhaust pipe 6. In some embodiments, the deposition, etching, and / or surface treatment steps are performed in the same reaction chamber, so that two or more (e.g., all) steps can be performed without exposing the substrate to air or other oxygen-containing atmosphere.

[0068] In some embodiments, the flow of carrier gas into the reaction chamber 3 can be achieved using a flow path system (FPS), with a bypass line with a precursor reservoir (bottle) in the carrier gas line, and switching between the main line and the bypass line. When only carrier gas is intended to be delivered to the reaction chamber, the bypass line is closed, whereas when both carrier gas and precursor gas are intended to be delivered to the reaction chamber, the main line is closed and the carrier gas flows through the bypass line and exits the bottle together with the precursor gas. In this way, the carrier gas can be flowed into the reaction chamber and the precursor gas can be pulsed without substantial fluctuations in the reaction chamber by switching between the main line and the bypass line.

[0069] Those skilled in the art will appreciate that the apparatus includes one or more controllers 26 programmed or otherwise configured to cause one or more of the method steps described herein. As will be appreciated by those skilled in the art, the controllers are in communication with the various power sources, heating systems, pumps, robotics, and gas flow controllers or valves of the reactor.

[0070] In some embodiments, a dual chamber reactor (two zones or compartments for processing wafers located close to each other) can be used, and reactant gases and noble gases can be supplied through shared lines, while precursor gases are supplied through non-shared lines.

[0071] The exemplary embodiments of the present disclosure described above do not limit the scope of the present invention, as these embodiments are merely examples of embodiments of the present invention. Any equivalent embodiments are intended to be within the scope of the present invention. Indeed, various modifications of the present disclosure, in addition to those shown and described herein, such as alternative useful combinations of the described elements, may become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to be included within the scope of the appended claims.

Claims

1. A method for fabricating a structure including a high aspect ratio feature having an aspect ratio of 25 to 150, comprising: a. providing a substrate having one or more layers including a surface and a recess in a reaction chamber; b. forming a first carbon layer on the surface thereby at least partially filling the recess; c. partially removing the first carbon layer; d. forming a second carbon layer overlying a remaining portion of the first carbon layer; e. partially removing the second carbon layer such that a remaining portion of the second carbon layer is substantially flush with the opening of the recess; f. depositing at least one additional layer overlying a remaining portion of the second carbon layer; g. etching said at least one additional layer to form an opening in a remaining portion of said second carbon layer.

2. The method of claim 1 , wherein at least partially filling the recess comprises forming a void in the recess and beneath the first carbon layer.

3. The method of claim 1 or 2, wherein the initial fluidity of the first carbon layer is greater than the initial fluidity of the second carbon layer.

4. The method according to claim 2 or 3, wherein after the step of partially removing the first carbon layer, remaining portions of the first carbon layer still continue to form voids in the recesses.

5. The method of claim 1 , wherein partially removing the first carbon layer comprises removing at least some of the first carbon layer from the recess.

6. 6. The method of claim 1, wherein the step of forming the first carbon layer, the step of forming the second carbon layer, or both steps comprises plasma enhanced chemical vapor deposition (PECVD).

7. The step of forming the first carbon layer, the step of forming the second carbon layer, or both steps are selected from the group consisting of a carbon nanotube having a structure represented by formula C ｘ H ｙ N ｚ 7. The method of claim 1 , comprising providing a precursor represented by the formula:

8. 8. The method of claim 1, wherein the step of forming the first carbon layer, the step of forming the second carbon layer, or both steps comprises a plasma treatment step.

9. 9. The method of claim 1, wherein the step of forming the first carbon layer, the step of forming the second carbon layer, or both steps includes manipulating a film density of the first carbon layer, a film density of the second carbon layer, or both, by controlling one or more of radio frequency (RF) power, exposure time to a plasma, and bias radio frequency (RF) power on a susceptor stage / susceptor.

10. 10. The method of claim 9, wherein the radio frequency (RF) frequency is in the range of 2.0 MHz to 27.12 MHz and the frequency of the radio frequency (RF) bias on the susceptor stage / susceptor is in the range of 400 kHz to 800 kHz.

11. 11. The method of any one of claims 1 to 10, wherein the temperature in the reaction space during the step of forming the first carbon layer, the step of forming the second carbon layer, or both steps is less than 100°C.

12. 12. The method of any one of claims 1 to 11, wherein forming the first carbon layer comprises exposing at least one precursor to a plasma having a radio frequency (RF) power of 50W to 300W.

13. 13. The method of any one of claims 1 to 12, wherein forming the second carbon layer comprises exposing at least one precursor to a plasma having a radio frequency (RF) power of 50W to 300W.

14. 14. The method of claim 1, wherein the at least one additional layer comprises one or more silicon oxide layers, one or more silicon nitride layers, or both.

15. 6. The method of claim 1, wherein the first carbon layer is formed without a plasma treatment or using a weak plasma treatment with a radio frequency (RF) power of 50 W to 300 W, such that the first carbon layer has a high flowability with a B / T ratio of 1.5 or more and a low etch selectivity with a ratio of an etch rate of the first carbon layer to the one or more layers being less than 2.0, the B / T ratio being the ratio of a thickness of a film deposited on a bottom of a recess before the recess is filled or partially filled to a thickness of a film deposited on a top surface in which the recess is formed.

16. The method of claim 15, wherein the weak plasma treatment comprises an exposure time to plasma of between 1.0 seconds and 10.0 seconds.

17. The method of any one of claims 1 to 15, wherein the second carbon layer is formed using an intense plasma treatment with a radio frequency (RF) power of 100W to 800W.

18. The method of claim 17, wherein the intense plasma treatment comprises an exposure time to plasma of between 5.0 seconds and 30.0 seconds.

19. 19. The method of claim 1, wherein after the step of partially removing the second carbon layer, at least a portion of the second carbon layer remains in the recess.

20. 20. The method of claim 19, wherein the portion of the second carbon layer remaining in the recess has an upper portion that is substantially flush with a surface defining a recess opening.

21. 21. The method of any one of claims 1 to 20, wherein the step of partially removing the first carbon layer, the step of partially removing the second carbon layer, or both steps comprises plasma etching with one or more of an oxygen-containing gas and a hydrogen-containing gas.

22. A system for carrying out the method of any one of claims 1 to 21.

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